saving got stuck after delete duplicate vertices

[thuliu-yt16]

After loading a mesh, I delete duplicate vertices and then export it. The saving procedure got stuck and the memory meshlab occupied kept increasing until it was killed. The same issue happens in both pymeshlab and meshlab.

Version: 2023.12.post1

Step to reproduce:

1. import a mesh (https://drive.google.com/file/d/1lNXmUIwyFxTrOdnft3r757UIyjVdp6Tf/view?usp=sharing)
2. filters -> clearing and repairing -> remove duplicate vertices
3. export mesh as an obj file (polygonal, without normal)

It just hangs on forever.