When ungrouped, the AI is moving non-controlled characters off of oil. This triggers traps in the witch cave

Has the AI always done this?
Loaded up a save from last year.
Ungroup all characters. Put one on oil
Highlight another, one on oil steps off.
Then add the other 2 characters to group with the one who stepped off the oil
Then select the one who stepped off the oil due to AI and the other 2 in their group will step onto the oil.
I'm sure it didn't do this before

Repeat, this is when ungrouped, they're not moving to follow the selected character in a group, the AI is automatically moving ungrouped uncontrolled characters to the nearest un-surfaced point.