Anomaly Map Bosses in SSF

I played trade at the start and have seen the sealed vault anomaly map. I know it's supposed to be in a mountain biome and I've spent countless hours searching for one in SSF but haven't seen a single one. I have more citadels than I know what to do with, have seen ever single other anomaly map countless times but never the sealed vault. I need this map for the lineage supports it drops but if I can't find one soon I'm going to quit the league.

I'm about convinced that this is an bug and the map just isn't spawning within SSF. I don't know how that could be possible but that's my only assumption. Has anyone in SSF actually seen one?