Sorry, I did not realize that was the problem. You might try re-installing Bambu Studio. The recent releases seem to cause trouble for some people and is solved by re-installing.
Had this issue.
Seems related to an old and/or corrupt process file in a .3mf.
Once I figured out which file was causing it, I deleted all the processes in library/applicationsupport/bambustudio/user/<user#>/process so I could open bambu studio
then loaded the file
then resaved the processes
then resaved the file