All monsters of 1 map spawned in a small portion of the map (might be abyss related)

I played my first abyss map (Tier 5) and had this weird issue in where seemingly all monster of the map spawned near the abyss. Which resulted in 1 Crash and strong fps drops due to the sheer amount of monsters in that area.

I was able to clear out that thing and explored more of the map since I was still missing a marked ritual but the map had no visible rituals and no more monsters behind the area of my abyss. The whole scene was very bizzar. But I recorded everything and made a small video out of it since it was kind of fun as it was frustrating to Zerg through where you can see this yourself.

https://www.youtube.com/watch?v=hqEdEdZ4e8U