Eventually, after leaving my machine up and/or asleep, the taskbar thumbnails don't respond.
Does the issue happen only when 7+ Taskbar Tweaker is running? What do you mean by "don't respond"? Which options are you using with 7+ Taskbar Tweaker?
When I hover over them they don't show up. Clicking the button is just fine. I closed 7TT and they came back. I'm on Windows 10 Creators.
Here's my options.
Please check if that's the bug you're having:
Customer support service by UserEcho