I use a custom function for an SAP application that pushes data to a database:
=PutCtData("PKAMOUNT","AMOUNT",A1:A5,)

As soon as this function is included in a spreadsheet, regardless of whether
I am connected to the database or not, I can only paste once after copying
(vs. typically being able to paste as many times as I want to before the
clipboard is cleared). It's as if the 'calculate' F9 function is being run
after each paste.

Another similar formula to pull from the database does not cause this problem
=GetCtData("PKAMOUNT","AMOUNT",A1:A5,)

Any suggestions on how to deactivate this, or why it would arise?