This has happened to me on 2 separate accounts today.
I import the model into studio, I place object at location, my entire studio freezes up and everything is now in extreme lag. Even my mouse movements on my entire desktop is down to a crawl. I have to force quit studio.
When I reopen and try to build in a different dev branch, everything is running super smooth. Reopen the branch I imported in, back to extreme lag.
Could you provide some logs and a video of this happening, please? You can find how to do that here: How to post a Bug Report - Bug Reports - Developer Forum | Roblox
Closing this as we require more information in order to investigate this issue. If you run into this issue anytime in the future, please file a new bug report following these guidelines: How to post a Bug Report - Bug Reports - Developer Forum | Roblox.