Getting hella errors and crashes on upcoming project

Partner Rank: 1
Verification builds: 1.21.0.21
Regression Builds: 1.20.80
Summary: Getting hella errors and crashes on upcoming project
Repro Steps:
open the map sent to greggo
Observed Results: 5/10
The following assertion happens and a bunch of content logs in recipes and items. if you dont get any errors, play for a bit then leave the world and open it again.

Expected Results:
No errors when playing the content, because it's perfect and error free
Screenshots / Videos attached: No
Notes: