My Epson scanner is much older than your 750 - it's a 500 - but I experience similar problems using Epson Scan when I preview MF negatives. For some reason the software has all kinds of trouble recognizing frames and cuts frames in half as you describe. It has started doing the same with 35mm lately, although only occasionally, while it never did it in the past.
I gave up trying to solve the problem with MF years ago and just uncheck the [thumbnails] box and preview the frames one at a time. It's a hassle and I wish I didn't have to do it but I'm happy enough with the resulting scans that I've just sorta made peace with the process.