Sorry to know that you are having issues while saving.
We will take a look into this. Could you please share the f3d file and the steps to reproduce this issue? Also could you please send us the Fusion360 diagonistic log file (Help > Support and Diagnostics > Diagnostic Log Files).
I have the same problem. I am getting the error message "Failed to save T-spline file" but I cannot see where there would be a fail. I exported the file and then tried to upload it again but then it says it is the wrong file or unable to read. Is it possible to fix? How did the previous person solve the situation?
