PBR textures persist after deactivating all resource packs

After deactivating PBR resource packs, animated blocks that previously had a MER texture will use that texture. These blocks will continue to use the MER texture until the game is restarted, even if you apply a different resource pack. If you apply a different PBR resource pack, the block will use the new MER texture.

Expected Result:
Textures will return to the default Minecraft ones.

Observed Result:
Blocks that previously had a MER texture will use that one.

Steps to Reproduce:

1. Open a world while using a PBR resource pack
2. Exit to the title screen
3. Deactivate all resource packs
4. Open a world
5. Any blocks that had a PBR texture will have that texture override the main texture

Screenshots:
Before, with no Resource Packs applied:

With a PBR Resource Pack applied: (left: Kelly's RTX, right: Defined PBR)

After, with no Resource Packs applied:

Notes:
Applying a different resource pack does not fix this, unless it is a PBR resource pack which has a MER texture for the affected block.

At certain angles/distances, the correct texture will appear.