mobs.json in multiple maps is not validating correctly despite being valid json

Partner Rank: 1

Verification builds: Beta 1.12.0.2 release 2039725

Summary: mobs.json in infinity plumber is not validating correctly despite being valid json. This prevents all the custom models from loading

Repro Steps:

• Download and open Infinity Plumber
• Activate Cheats
• Note the content errors on the top
• do /summon slime

Observed Results: the mobs.json doesn't validate, all the custom mobs do not look correct as a result. For example the slime doesn't have the correct model and looks like a cube and not the perfectly crafted pile of poop.

   

Expected Results: the mobs.json should validate correctly as it does in jsonlint and other online validators. The slime should look like a jumping pile of poop as well as others.

 

Screenshots/Videos attached: Screenshots above.

Notes:
This world contains a very simple behavior pack for reproducing the issue.