Sometimes the Trim brush acts as Slice. I can not reproduce the conditions when it happens. Also, the tool tip on screen says “Slice” when the brush says “Trim”. (I understand that Trim = Slice + delete + Close Holes)
I have seen this post but it doesn’t make sense. I don’t have to do the solution when it as acting normally
“You have to start and end your trim curve with holding both CONTROL + SHIFT.
When you hold CONTROL+SHIFT to start the trim curve and then you only hold CONTROL and tap ALT to make the curve anchor point, you have to re-press CONTROL + SHIFT at the end before you let go. If your only holding control it becomes a slice curve.”