Here are some issues I’ve found so far in both SP and MP:
In Unforeseen Consequences, the black security guard dude who helps you doesn’t gesture (or really move) anymore during the “Gordon! Man am I glad to see you” sequence, as well as his face expression changing very disjointedly. Additionally, when he gets to the main lobby and tries to call for help, he doesn’t play the “press button” animation and instead magically turns on the radio with his mind and speaks the lines while in the idle animation.
In the encounter in WGH where the scientist goes “Rescued at last!”, if you save him, he doesn’t say the “Goodness gracious! I do believe he was trying to kill me!” line and will remain silent.
Sometimes, in Surface Tension. when the Osprey tries to drop off grunts, they get stuck inside the Osprey and will cause the Osprey to stop moving and also stop dropping grunts. The grunts will be inside the Osprey’s hitbox, so they are basically unkillable and it messes up the entire sequence.
The HECU will still occasionally rush your position with reckless abandon if you hide behind cover away from their line of fire, albeit slower.
When you hit a soda machine, all the cans have no collision and come out in the same place at the same time resulting in a giant blobby mass of soda cans.
In dm_subtransit, if you’re positioned correctly the tram can push you into the railing and get you stuck inside it.
Sometimes, MP playermodels will go into a T-pose.