Plotting FacetGrid

Question

I have this Dataframe:

OverallQual     Foundation
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               BrkTil
8               PConc
8               PConc
8               CBlock
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               BrkTil
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               Wood
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               CBlock
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
8               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               CBlock
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
9               PConc
10              BrkTil
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              PConc
10              BrkTil
10              PConc
10              PConc
10              CBlock
10              PConc

And if I count the values of each Foundation in every OverallQual, it show the result like this:

OverallQual  Foundation
8            BrkTil          2
             CBlock         10
             PConc         155
             Wood            1
9            CBlock          1
             PConc          42
10           BrkTil          2
             CBlock          1
             PConc          15
Name: count, dtype: int64

I want to produce a faceted grid of bar plots, one for each OverallQual and then colour the bars according to the Foundation column. I try to use FacetGrid in this case. Here's my code

df_exerc_fg = sns.FacetGrid(df_exerc, col='OverallQual', hue='Foundation',palette='tab10')
df_exerc_fg.map(sns.barplot, 'Foundation', 'OverallQual')

But the result is not like what I expected. I think it's not plotting correctly.

But when I compared this with subplot in this code:

fig,ax = plt.subplots(1, 3, sharey=True, sharex=True, figsize=(15,5))
plt.suptitle(str.title('Material pondasi yang sering dipakai untuk grade 8-10'), fontsize=16)

ax[0].set_title('Overall = 8', fontsize=14)
sns.barplot(x = train_house['Foundation'].loc[train_house.OverallQual == 8].value_counts().index,
             y = train_house['Foundation'].loc[train_house.OverallQual == 8].value_counts(),
             hue = train_house['Foundation'].loc[train_house.OverallQual == 8].value_counts().index, 
             legend=False, 
             palette='tab10', 
             ax=ax[0])

ax[1].set_title('Overall = 9', fontsize=14)
sns.barplot(x = train_house['Foundation'].loc[train_house.OverallQual == 9].value_counts().index,
             y = train_house['Foundation'].loc[train_house.OverallQual == 9].value_counts(),
             hue = train_house['Foundation'].loc[train_house.OverallQual == 9].value_counts().index, 
             legend=False, 
             palette='tab10', 
             ax=ax[1])

ax[2].set_title('Overall = 10', fontsize=14)
sns.barplot(x = train_house['Foundation'].loc[train_house.OverallQual == 10].value_counts().index,
             y = train_house['Foundation'].loc[train_house.OverallQual == 10].value_counts(),
             hue = train_house['Foundation'].loc[train_house.OverallQual == 10].value_counts().index, 
             legend=False, 
             palette='tab10', 
             ax=ax[2])


plt.show()

It plot the data perfectly, like this.

The chart in FacetGrid is not plotting correctly. What am I missing in my code?