Client throws errors on world load with custom blocks

Partner Rank: 3

Partner Team Reporting: Imagiverse

Verification builds: 1.18.0

Summary:
Client throws errors on world load with custom blocks.

Impact:
Content Blocked by Certification

Repro Steps:
Download and play Designer Furniture: Winter
Repro Rate: 3/3

Observed Results:
On load, error is thrown: "[Blocks][error]- Loading levelchunk 192 33 from savegame | subchunk 5 | deserializing subchunk palette | block of name 'imagiverse:pattern_gray' does not exist. did you just add an updater with a bad block name?
Error appears for all custom blocks in pack.

Expected Results:
Custom blocks loading with no errors.

Screenshots/Videos attached: Yes.
Regression Builds: Unknown