I created a new payment, entered a reference and selected a category. The category wasn’t remembered. In fact, I think I had to go to the relevant transaction and set it a couple of times for it to save it.
More important though is that it didn’t remember the reference. So, whilst that went through the first time, the next time I used it (from the recent list), the reference was blank and I didn’t notice, which means the payee has no idea where it came from.