Looks like something broke
Yeah, I was just coming here to report this. It doesn't even need to be from the FSS. If you just drop into a system with a close belt, it'll just loop the discovery messages for the clusters over and over.
I can assure you that i already had this before this latest patch. Actually it was always like this for me, at least since the beginning of January, seeing overlapping messages due to several clusters on a single asteroid belt.