I cloned https://gerrit-replica.wikimedia.org/r/mediawiki/core and noticed that the latest commit on its master branch is rMWb11c3dcc1374b459c40d793944feb0226ce6050c, not rMW8e9a308d3c531ff25c0b4fd17e38265dad6f5864.
You can see this in rMW, which mirrors the replica. Notably, rMW8e9a308d3c531ff25c0b4fd17e38265dad6f5864 is known to rMW, suggesting that replication broke sometime after 3:46 PM.