Hi, I'm also seeing this issue. I've just made this account, so I can't attach to posts, but here's a link to a Google Drive folder with the relevant files:
https://drive.google.com/open?id=15IGFhiRgKLIole-4OC12IFcbDeV99nuNPer the template:
1. An explanation of the bugHelp window in battles is always on and flickering. The flicker happens with 60fps battles enabled, either interpolated or non-interpolated. It does not happen with 60fps battles disabled. It appears to switch between flickering at 15hz and 30hz. When it flickers at 15hz, all battle animations run at half speed. It does not affect the rest of the UI, which still runs at 60fps with no slowdown.
My save file was created in a game running Reunion r06b, which was updated to r06d. It has the help window mapped to Select rather than L2. When 60fps battles are enabled, pressing Select does not turn off the help window, but does interrupt the flicker very briefly, for a frame or two. When 60fps battles are not enabled, pressing Select toggles the help menu as usual.
I did not see this issue in r06b; it only started happening as soon as I installed r06d.
2. Does the bug happen at same point more than once?It happens in every battle. The issue persists even after restarting the game or rebooting the computer.
3. App.log (found in root folder)In Google Drive link
4. Reunion.log (found in The_Reunion folder)also in Google Drive link
5. crash.dmp (found in root folder)Not a crash, so no crash dump available
6. Your save file from just before the crash or hangNot a crash, but I've included a save file anyway.
7. Audio.log (found in The_Reunion folder)Not an audio issue, but I know bugs can turn up in the weirdest places so I've included that as well.
8. Your CPU specIntel Core i708650U; 1.9 GHz
9. Your operating systemWindows 10, version 1909
It may also be useful to note that I'm using a Microsoft Surface Book 2 with discrete graphics. I don't know how useful that information may be to triaging the bug, but if anyone else runs into the same problem on the same hardware then at least they'll know it's not just them.
I've also included hext.log in the google drive folder, since you mentioned above that there might be a hext issue. As for the exe file, I have not modified any executables in this installation, so they came straight from Steam.