XP counters - potential bug

Opponent had Meren of Clan Nel Toth and Champion of Lambholt out.
I had Humility out.
I cast Wrath of God and opponent got an XP counter from meren.

I don't think that should have occurred?

Reproduce the interaction involving Meren of Clan Nel Toth, Champion of Lambholt, Humility, and Wrath of God, then trace the card and experience-counter handling used for those effects. Confirm the intended rules outcome and add a regression test showing whether casting Wrath of God should grant the opponent an experience counter.

Written by the indexing model from the issue text.