The bug

Most files in behavior packs produce content log warnings when invalid keys are present. This is not the case for loot tables.

How to reproduce

1. Download and open the attached world
2. Kill the pig named "key"

Expected result
Content log errors for:
invalid not valid in root of file
invalid not valid in pools entry
invalid not valid in entries entry
invalid not valid in functions entry
invalid not valid in conditions entry

Actual result
No content log errors for these things appear. The invalid data is loaded.

Notes
The vanilla behavior pack contains these kinds of schema errors.