Editor/Model bug: Editor infinitely loading when model is placed on the map

[VaaL]

So, I Reforged this WoW model, first converted it to default WC3 mdx (Format 800), then made all the modifications to transfer it to Reforged MDX (Format 1100). The mdx 800 works just fine, but the Reforged version has some issues. When I import the model and the textures to a new empty map, save the map and test it - it all works fine, the model is displayed properly and no bugs can be noticed.
BUT
When I close the World Editor entirely, and reopen the map -> it's giving me the infinite loading IF and only IF any instance of the model is placed on the map.
So, if I just have the model imported properly - it all works smoothly, but if I have a unit placed on the map, for example a peasant using my custom model on the map, the editor bugs.
Never had this issue with any model before.
Any idea what's the issue?
Wondering if it's a 2.0 issue or just a model issue.
Here's a link to a test map with the model imported:

TESTT_00041.w3m

drive.google.com

 

[Daffa]

Have you tried checking with Sanity Tester?

 

[VaaL]

Have you tried checking with Sanity Tester?

I thought this is an old tool for old models, would it work for Reforged models too?
Upd: As I thought, it doesn't recognize version 1100