CGATS Smoother.xlsb not working

I cannot paste Lab data into the curves tab of the CGATS Smoother.xlsb. I get a message that say this is a protected sheet. However, the numbers version of this tool works fine, as well as the PP 2.2.2.xlsb workbook. I am running Monteresy on a MacStusio (M1).

Thoughts?

thanks.
Michael