Are access token and refresh token valid after Fitbit user migrate to Google account?

Question

I am working on a clinical trial to get users' wearable data from Fitbit. We developed a simple app to ask users to authorize to get the access token and refresh token. Previously, most users were using a Fitbit account rather than a Google account. But now some users may migrate their accounts to Google and we lost some users' data but have no idea about it. We are not sure if they are related. After migrating to Google, I wonder, do I need to ask users to authorize again to get a new access token and refresh token, or I can still use the old token to fetch data?

In short, if Fitbit users migrate their accounts to Google accounts, are the access token and refresh token still valid for communicating with Fitbit?

I only have a Google account to log in but don't have a Fitbit account.

Updated: This question is solved by the Fitbit developer. Here is the reply:

Users migrating from Fitbit accounts to Google accounts have no impact on their active access tokens and refresh tokens. You won't need to ask your users to go through the authorization flow again, it should be a seamless transition.

If you are seeing errors, there may be a possibility that the user just simply revoked access to your application through their account settings.