Cannot write to Google Sheet

Hi Everyone

I’m getting better at Thunkable but some things still baffle me. I’ve been trying for two days to figure out why one sequence in my block structure works but another, near-identical one fails. Here’s the full structure:




I’m trying to check if the username is the same as the “Perf Username” in a data table (“Perfs Table”) and, if so, the app first populates a list variable (MyPerfs), reversing the order so that most recently added data rows are on top. It then is supposed to write each row where there is a match to a new data table (“Session Display Perfs”). As you can see I have added several debuggers to identify where the problem lies and I’ve narrowed it down to “in list app variable MyPerfs insert at last…” Although the loop is identifying username matches it is not writing them to the list variable and I cannot figure out why, given I’m using exactly the same system as for the MyTexts routine above, which works 100%!

It’s so frustrating! Does anyone have any idea what might be going on?