Ritual bug?

Running map with maven was 3/4 last ritual in boss room can't activate the ritual?

https://gyazo.com/0942343558838de906d4b58be16c464c
https://gyazo.com/0c08362946c71da1a156df7e0768fb0a
I can still open rewards and buy things but no 4th ritual even says 1 Left
https://gyazo.com/3bb9536a9bd3a2d50047f95e7d222feb

i am getting so many of these

is it the extra maven bosses?

i have had these with zero monsters left in map, so seems like a bug for sure.