I dealt damage for a couple turns with Adelbert Steiner and his lifelink gave me life as expected. Then one turn afterwards, I attacked and no life was given. There weren't any cards in play that would have negated lifelink. Screenshot shows the board with all cards that were in play when lifelink didn't grant life (screenshot was taken the turn after mine after losing the game).

I would expect Steiner's lifeline to grant 5 life in this case after damage was dealt.

MTGA version: 2025.52.40.3615.1192642

MacOS 14.7.1