SMS Profile Icons Missing in Pushbullet

Question

For the past several months (maybe even a year, I had hoped an update would fix it), the custom user profile pictures that are displayed next to each person in the SMS section of PushBullet have been missing.

On the PC app, this causes the pop-out SMS windows to only have the letters SMS where the top expand/collapse circle should be - greatly reducing the clickable area.

On the web, I can see those images are not loading there either, and I can see part of the default missing image icon and the image title text where the image should be. Here's a screenshot.

I also see these images are served from pushbulletusercontent.com and trying to view the image directly displays an XML access denied message.

I'm not sure if there is a way to reset these images or what else could be done to fix the issue. Any ideas?