Dread Return Flashback ability not avaliable.

I was playing a UB Delver Pauper deck with Murmuring Mystic and a copy of Dread Return. I had accumulated about 6 tokens when M.M. was killed, I tried flashbacking Dread Return in my graveyard but the vard didn't give me the option. It was main phase, I had the priority but nothing happened by clicking the card.

I had a Deep Analysis too and was able to flashback it no problem instead, so no graveyard or priority bug.

Reproduce the interaction using a Pauper UB Delver deck with Murmuring Mystic, Dread Return, and Deep Analysis, after the Mystic is removed and tokens are available. Trace the card and flashback handling for Dread Return and compare it with Deep Analysis; done means Dread Return offers its flashback action during the main phase when its cost can be paid.

Written by the indexing model from the issue text.