Spinning wheel Mac Studio while cutting footage

I'm trying to spot a sequence but my Mac Studio keeps loading after every 1/2 steps. The clips all have proxies. I have 4 different projects. 2 projects work fine, the other 2 including this one, keeps showing me the loading mac icon. I work on a new 2023 Mac Studio 32gb. The strange this is that 2 project work fine and 2 are not. What could be the case here?

I recorded a video to show what happens.