I upgraded from 2.9.5 to 2.10.4 of the UiPath.Excel.Activities and when my unchanged Bot ran it encountered a new exception with message “The cell or chart you’re trying to change is on a protected sheet. To make a change, unprotect the sheet. You might be requested to enter a password.” - this is true in this case. However the cell I was writing (ExcelWriteCell) to was specifically unprotected.
In 2.9.5 this operation worked, in 2.10.4 the error occurs. I reverted back to 2.9.5 and the unchanged Bot is working again.
I have not yet gone to the 21.* version of the activity to see if it remains in later versions.