There is a bug with the Bubble “PATCH” implementation.
If you need to combine two tables (and you really do) to do a PATCH from an input that is updating rows on the Bubble table, then you will most likely have two fields named the same thing.
So DATE from Bubble and DATE (1) from a Google Sheet (as an example).
When you PATCH Bubble’s DATE field with {Date(1)} (chosen from the list provided) it will Ignore that you want the updated field and always take the field from Bubble (so never updates).
The only way around this (other than it being fixed) is to make sure the fields are not called the same thing. It makes it all quite complicated, however.