I had a similar issue on an non-BMW MT back in the day, it started popping out of 1st when it felt like it. It was more prone to happening under heavier acceleration. I even tried several MT fluids with different friction modifiers over the course of a week or two hoping for any positive effect. That was wishful thinking. I was pretty convinced it was synchros, but it turned out to "simply" be a broken dog ring retainer. Cheap part, but, of course, the tranny had to be taken apart to find the real issue and fix it.
27K is really low mileage to be having tranny problems
