Tinybones card text says exiled cards with stash counters can be played from exile during my turn using any mana. This is not how it is working

Play Tinybones
Play Pilfer to choose a card for opponent to discard
Discard card is exiled and appears for me to cast
In this case the card had cost of 2W and 3 any mana
I had 6 black mana untapped
Trying to cast the exiled card brings up the message I need 2W and 3 any mana
Expected: Any mana can be used to cast cards with stash counter from TinyBones, so 5Bl should have worked

This is on iOS client v2025.51.0