So I had previously done this with on my priest several times with my husband and I don’t remember this being an issue… but just now I did it by myself on my sham and the part where waves come out seems bugged to me. Within a matter of a few secs I was on 20+ waves without really killing anything. As you can imagine, I ended up dying. I don’t think 20 waves are supposed to come out simultaneously but maybe that’s just me. 
Somehow I managed to get through it when I popped but it seems broken. It was def very unexpected.