As of 3.18034.7 my Collections do not work with my SQL connector. Before 3.18034.7 I could Collect and then reference records in my SQL database, but now I receive "Invalid formula. Expected a value compatible with 'Data Source'."
I use a collection as a data source in a gallery, but then when I click on an item to view it's details, it goes to a form with the SQL database as the datasource. This was working before 3.18034.7 but it seems after this update, I am getting the Invalid Formula error.
I actually solved this issue! For some reason, my Collection I was using got merged with another Collection so the fields were different. I ended up creating a new Collection and now it's working fine.
It seems that the new version of Powerapps had some side effects, but I worked through them!