Experiencing the same for several months. Refreshing data source, breaks the data binding on the fields. I have to delete part of the ["Value"] in the DisplayFields and SearchFields properties and then re-enter it to bring back the choices. This has to be done for all fields individually. On top of the hassle its not clear, that this bug i happening. You have to test the fields in preview to see if the fields are broken or not. There is no PowerApps error on the fields.
OK, thanks - its not just me. I am also noticing that when you type in apps, there is say a 2-5 second delay in the say "connection" to any fields etc.....So you can be typing something that looks like its gone in, but it hasnt. You then end up having to delete a bit, then gradually type it in bit by bit and "add to it" - i.e. when the autofill/pop up text appears and you add from there, things go ok etc. This (I guess) could be our local network causing lag etc.....But yeah, having to go back and rebind items is really getting my back up to say the least.