I’m by no means an expert, but I think setting clear goals for yourself is a good way to avoid this. I also distinguish between time spent playing my ukulele and time spent truly practicing. Truly practicing would be working on technique, theory, or new songs. Playing is having fun with songs I already know.
To answer your question, yes I think it’s normal. Maybe what you are doing isn’t the most efficient way, but the important thing is that you are enjoying it.