Premiere Pro attached proxies glitching

Here are my system settings:

Premiere Pro 24.3.0 (build 59)

MacOS 14.4.1

Procesor: 2.4 GHz 8-Core Intel Core i9

Graphics: AMD Radeon Pro 5500M 8 GB
Intel UHD Graphics 630 1536 MB

I've converted my iphone 4k footage to H264, and I've converted the footage that was at 30fps into proxies (this because I read that variable fps wouldn't work for proxies). I started a new project and put all my H264 footage into the media bin, then I selected the 30fps footage and attached the proxies. When I enable proxies and hit play, however, the footage immediately glitches. When I import the proxies on their own they play fine, so it's not an issue with the proxies themselves. I'm really not sure what to do. I turned off the mercury playback enginge and that also didn't help. Any ideas? I would like to avoid remaking all the proxies as it usually takes a whole day to do. 

I did rename both the original files and the proxies as they both had a _1 on them, so I changed them back to the original names in order to try to relink them to the original project. This didn't work though, which is why I started a new project.