Been focusing on another project for 2 weeks and when I started to edit my PowerApps canvas today I had errors on the galleries. This code has been working for months and I am not understanding what has changed. If Microsoft has changed things or what could be the issue.
Here are my examples.
On Gallery with a list of Courses. I have counted the rows of a Bookings table linked to the Course. On the Bookings table I have a lookup to Courses. I have used this formula to count the rows in that related table. Why has it stopped working when it has worked before?

Other example:

Same related table lookup that is references. I'd love to understand what has changed.
Kind regards.