Hi! Since 10.70 works correctly and 10.75 does not, and since the upcoming ST11 release is still a way out, I suggest trying the one that comes with version 10.74 and working your way back (10.73, 10.72, 10.71) to find the latest working release, so you can get your project ready in time.
https://www.thimeo.com/documentation/ve ... story.html will show you any changes you should be aware of regarding processing changes.
https://download.thimeo.com/ThimeoWatch ... 4_1074.exe
https://download.thimeo.com/ThimeoWatch ... 4_1073.exe
https://download.thimeo.com/ThimeoWatch ... 4_1072.exe
https://download.thimeo.com/ThimeoWatch ... 4_1071.exe
Good luck with your project.
edit: Also be sure to check the latest betas. I don't see anything about Watchcat in the notes so far, but this issue may be fixed soon.