Yes mesh is corrupted.
Execute the following script, It'll detect the mesh corruption and will also fix the mesh

import bpy
for obj in bpy.data.objects:
    if obj.type == "MESH" and obj.data is not None:
        if obj.data.validate():
            print(f"Error found: object {obj.name} had invalid mesh data!")

@Philipp Oeser (lichtwerk) had shared this script in T93972 :)

I don't know how I managed to corrupt it.

Unfortunately unless there are clear instructions on how to reproduce it from scratch we cannot debug this any further.
Things that may cause mesh corruption: Importers, development versions of Blender, modeling tools.

Unfortunately unless there are clear instructions on how to reproduce it from scratch we cannot debug this any further.

This is going to be hard. During that session I was working on a desk and playing around with modifiers and only realized the object was corrupted much later. I wasn't really doing anything esoteric, for the specific object I was only using subdiv and maybe decimate and triangulate. Apart from that, there is no way I can remember the specific sequence of action. The culprit might not be the modifier. There might also be a chance that me working on another object in the scene might have done something. I was hoping the save file might give enough of a clue, but nevermind it for now. I'll keep an eye open in the future in case I run into the bug again. Please feel free to close this.

Hi, thanks for the information.
I think we can close this report if source of the mesh corruption is not known to us.
@Philipp Oeser (lichtwerk) & @Hans Goudey (HooglyBoogly) , thoughts?

If we have no way to reproduce, we usually close the report, yes!
(we can always reopen in case these repro steps are found later)