Achievements disabled in my Realms world due to an external behavior pack

Brief description of the issue

Achievements became disabled in my existing Minecraft Bedrock Realm. Minecraft shows the reason as “Activated external behavior pack”.

Steps to reproduce

1. Open an existing Minecraft Bedrock Realm with the Add-Ons listed below.

2. Enter the Realm world.

3. Leave the world and open the world settings.

4. Change the difficulty from Peaceful to Easy.

5. Close the world settings and return to the Realm.

6. Check the achievement status.

Expected result

Achievements should remain available because I did not enable cheats or switch the world to Creative mode. Changing the difficulty from Peaceful to Easy should not disable achievements.

Actual result

Achievements became disabled. When I checked the reason, Minecraft specifically showed: “Activated external behavior pack”.

I did not enable cheats and I did not switch the world to Creative mode.

The Realm has these 8 Add-Ons installed:

1. Backrooms

2. Warpstones

3. Damage Indicators

4. Huggy & Friends

5. World Utilities

6. The One Who Watches

7. Security Specialists

8. Gravestone

All of these Add-Ons were working normally in the Realm before this problem occurred.

This is an existing Realm world, and I would like to keep playing on this world while earning achievements.

Could you please investigate whether this is an unintended bug in Minecraft Bedrock 26.52 involving external behavior packs/Add-Ons and achievements?

If the achievements were disabled because of a bug, I would also like to know whether achievements can be restored for my existing Realm world.