What do you have the params 1 set for on the pillars actor settings? The actors properties/misc/params 1.

Is your actor type 310? (Mover_FloorLowerOnce)
Check your sectors. Did you make small slope test sectors around the sector your platform is on?
Are all your platforms XY position in the same sector area?
Are your TID values correct?
Are your property values setup correctly?

Target ID = Sound ID to play
Health = Delay Time to reset back to it's original position (0 = no reset)
Attach Chance = Move Speed
Params 1 = Move Distance

And are there any actors outside sectors anywhere in your map? (Certain actors outside sectors can cause weirdness with the game. You can use the validation checker in the editor to help with that. Particle Emitters and pickups are fine, but things like enemies and platforms are the bad ones)

Is your actor type 310? (Mover_FloorLowerOnce)
Check your sectors. Did you make small slope test sectors around the sector your platform is on?
Are all your platforms XY position in the same sector area?
Are your TID values correct?
Are your property values setup correctly?

Target ID = Sound ID to play
Health = Delay Time to reset back to it's original position (0 = no reset)
Attach Chance = Move Speed
Params 1 = Move Distance

And are there any actors outside sectors anywhere in your map? (Certain actors outside sectors can cause weirdness with the game. You can use the validation checker in the editor to help with that. Particle Emitters and pickups are fine, but things like enemies and platforms are the bad ones)

Redid the sectors there, replaced the old actors with new ones, verified the map and even checked a vanilla map and the same thing happens.

You need to select the 4 vertices you made on the top of it and raise them up more if that's the case.

If your pillars are stopping at the correct length at -3, you have to fiddle with the sectors, because they're ultimately responsible for collision.

That seems to have fixed the issue, but I still don't understand why the other pillars I set up work just fine without doing that little trick.

Unrelated, but what do you guys use to record gameplay?

Shadowplay doesn't work with Turok anymore despite having the record desktop option turned on.

That seems to have fixed the issue, but I still don't understand why the other pillars I set up work just fine without doing that little trick.

Glad it's solved

Sector height for pillars is trial and error. I usually make sure they're a couple feet higher than the pillar because that works most of the time, but I always check anyway.

So both T1 and T2 get some Doom 64 pretty cool.