I had this happen to me as well. The Creaking mobs only responded to the type=creaking_transient, and when using type=creaking I got an error that said no valid targets were found.
I have gotten this bug as well. The version is MC Java 1.20.4 on a Paper MC server. It happened to me in a flat area, without the walls or ceiling that the OP said you'd need to do to recreate the bug, and it happened after I ate and then quickly opened the pause menu, and the shield was still up even in the pause menu, and a magma cube completely broke my shield. I submitted the bug here, since I don't know if it happening to me on Java in a different version with a different environment in game
Sorry, I just realized I linked the Google Drive folder incorrectly. The link txt is valid, but I will give you the valid link here: https://drive.google.com/drive/folders/10n-4pXAU4I5bWadL1v0XaT9Q8neX_fjE?usp=drive_link