Item frame model, shields, paintings and beds no longer support transparency in version 1.15.2. This was possible in all prior versions to 1.15.2.
This does not affect items placed in the item frame: they retain transparency levels.
this unfortunately limits custom resourcepacks in terms of what they can do with transparency, thus stifling creativity.
Find an example below, taken on 1.15.2:
[media]
Related issues
Comments

See MC-164001