I was playing one of my old levels, House of the Thwumps, when I came across someting quite abnormal in the mid-left corner of the house.

Here's a recreation:
I have a feeling it's got something to do with the glitch of entering a thwump with gold delay. The movement of the thwump keeps you from exiting it, then when you slide off it, you get this glitch.
Have any of you guys experienced this before? Feel free to share which map/s if you have, or any explanations that you might have different to mine.