I had this problem at a client today.  The solution was to put a tick mark in front of the = sign of that formula, turning it into a text cell.  When you run, even though it has the tick, FR parses it correctly.

This solution has worked for me at 2 different sites now (using Office 2016 Sage 300 2020) in the past year. The error was the "Desktop has stopped working" error after running through Statement Designer and FRView. Running the statement using Print Financial Statements does not error out, and it didn't error out on other workstations running Statement Designer (other WS were using Office 2013). Looks like it's fixed in PU 5 for 2020 as well. Thanks Jay! 

This solution has worked for me at 2 different sites now (using Office 2016 Sage 300 2020) in the past year. The error was the "Desktop has stopped working" error after running through Statement Designer and FRView. Running the statement using Print Financial Statements does not error out, and it didn't error out on other workstations running Statement Designer (other WS were using Office 2013). Looks like it's fixed in PU 5 for 2020 as well. Thanks Jay!