Hi,
There are tons of details missing from your description. but I am going to tell you whats wrong, which I have to guess about, because of the details.
1. You didn't show us a run with the error, PLEASE show the things you are asking help for
So please show us the error, the data inputs in the error etc.
But here are some other thoughts, just to make sure i have what its supposed to do correclty.
A) You should have a check for 0 rows right after your Get Items
B) You have a Filter Array, which is ok, but why not just put your Filter in the Get Items??
You don't need this. You can simply put your Filter in the Get Items. If you already have a Filter, I can help you make it so its just 1 if you want
C) Is your filter always for sure only going to return 0 or 1 rows?? Since it seems you are matching on an ID field, I am guessing its your unique column
so this is good.
Thoughts
-- I see no reason for this to create multiple Rows. EXCEPT if the flow is being triggered multiple times.
Can you please share the Output Run of a flow that created multiple Entries in Excel so we can debug that also.
I think we can help you, please just share the errors and the flow details above and :-) we'll get right back to you