I’ve had a similar experience with a Sandisk SSD.
I believe it’s because there is no safe removal mechanism on the iPad that allows for the drive to ensure all the data is written to the drive before it can be safely removed.
I was pulling my hair out (if I had any) about this and like you the “corruption” occurred at different times, in my case in one specific segment of my movie. I put this down to the fact that my drive wasn’t very full and the data got written to the same area each time I saved it.
Given the issues I had I was very fortunate to be able to return the drive for a refund, but it has made me very wary about using high capacity external drives with the iPad.
The following thread on the Apple communities Website explain my issue and the response given Which prompted my decision;
I was contemplating the Samsung T5 or T7 but didn’t know if there was any safeguard on the drive to suggest it was ok to remove it, such as a flashing or not flashing led. I’ve not found out yet, if you have the T5 maybe you can advise.