Edit # 2: Sorry for answering myself lol. I solved the problem, and if it can help someone, here's what I did:
- I went to check the location of my temporary variables (in windows: Control Panel | System and Security | System | Advanced system settings | Environment Variables)
- I modify the path of FME_TEMP. Instead of using \\\\ myserver \\ etc., I used a shortened path. To do this, I mapped a new network drive (example: Z: \\ FME_TEMP), and I used this path to specify the location of FME_TEMP in the windows variable environment.
- I restarted FME Desktop 2021, and everything works.
- I also checked that the temporary files were placed in the correct FME_TEMP folder. And now, feature caching is back to work!
Ciao!