Sorry to see that you're facing this problem. This looks like a bug and is not expected.
As a workaround please try the below steps:
These steps will correct the cache and hopefully will solve the problem that you are facing.
Another thing to try out if the above workaround doesn't work for you -
We are looking into the core issue, but the workaround could allow you to continue working in the meantime. Again, apologies for the inconvenience.
Regards,
Rushikesh Kadam.
okay I will try it soon.
So that sounds there is no way to save the changes that have been made so far? Oo
After trying the first solution this happened after reopening the project. Maybe it can help to find the solution.
The issue has been addressed. Please take the latest Fusion 360 update (2.0.9640).
https://www.autodesk.com/products/fusion-360/blog/january-2021-product-update-whats-new/
Regards,
Rushikesh Kadam
Great thank You! Awesome support