Sage of ancient Lore / Werewolf of Ancient Hunger

Werewolf of ancient hunger:
_rules Text
Vigilance, trample
Werewolf of Ancient Hunger's power and toughness are each equal to the total number of cards in all players' hands.At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature._

When transforming Sage of ancient lore into Werewolf of ancient Hunger by day/night cycle,
Werewolf of ancient Hunger is immediately put into the graveyard. It seems the game account its power and toughness to 0/0 even tho opponents and I had cards in hands.

The Sage of ancient lore side worked well and accounted correctly the numbers of cards I had in hand.

Thanks

No files, tests, or entry points are named. Reproduce transforming Sage of Ancient Lore into Werewolf of Ancient Hunger with cards in players' hands, then trace the card's power/toughness calculation; done when the transformed creature retains its hand-count-based power and toughness instead of going to the graveyard.

Written by the indexing model from the issue text.