This appended to me a few days ago whilst using the designer but in B4J, I was working on a new project for a client (I was about 4 or 5 days into development). I was working in the designer when all of a sudden blank notifications appeared and just kept repeating themselves over the top of the previous blank notification, I could just see it happening over and over and over again. Within just a few seconds there must have been two or three hundred blank notifications on my screen. The only way I could stop it was to use the Task Manager to end the B4J task.
Luckily I didn't really lose any code as I was working on the designer at the time and I had ran the project about 2 minutes earlier, I was just moving some views around. I didn't bother reporting this issue as in all the years I've been using B4X, I've never seen this happen before and I've not seen it since. It didn't occur to me to take a quick screenshot as I was too worried about my clients project, but yes this happened to me last week.