Backlog Mistcaller + Dryad Arbor = extra land drop

[Endrju]

Hello, I had the following situation:
in my opponent's turn I activated (sacrificed) Mistcaller. Later that turn opponent played Dryad Arbor as his land drop. Due to Mistcaller's effect still being active Dryad Arbor got exiled. However, opponent was able to play another land (Verdant Catacombs) afterwards. The following can be found in Comprehensive Rules:

305.2a To determine whether a player can play a land, compare the number of lands the player can play this turn with the number of lands they have already played this turn (including lands played as special actions and lands played during the resolution of spells and abilities). If the number of lands the player can play is greater, the play is legal

It doesn't specify that a land needs to be succesfully played - i.e. in this case my opponent has already played a land (which got exiled due to replacement effect) and he should not be allowed to play another one that turn.
(there where no effects in game that modify number of possible land plays for any player)

Event id: 259901645
Game id: 842807620 (2nd game in my 2nd match of the league)
It happened during my opponent's (DemonicTutors') turn 6.