Cross-platform saved heroes do not unlock previously earned mission achievements on another platform

Short description of the issue

Cross-platform progression works correctly between PlayStation 5 and Steam when using the same linked Microsoft account. My saved hero, progress, completed missions, and other character data are successfully available on both platforms.

However, achievements/trophies earned or completed on one platform are not granted on the other platform when loading the same synchronized hero.

This becomes a problem with achievements related to completing specific missions, side quests, or other one-time objectives. For example, if a mission has already been completed with the character on PlayStation 5, loading that same character on Steam does not unlock the corresponding Steam achievement.

Since the game already considers the mission or side quest completed, there is no way to complete the requirement again with that hero and trigger the achievement. The only workaround is to create a completely new character on the affected platform and replay the required content from the beginning.

Steps to reproduce the issue

1. Link the same Microsoft account to Minecraft Dungeons II on PlayStation 5 and Steam.

2. Play on PlayStation 5 and complete a mission, side quest, or objective that awards a trophy/achievement.

3. Confirm that the trophy is unlocked on PlayStation 5.

4. Launch the game on Steam using the same Microsoft account.

5. Load the same cross-platform synchronized hero.

6. Confirm that the character's progress and completed mission are correctly synchronized.

7. Check the Steam achievements.

Expected result

Achievements related to already completed objectives should be checked when a synchronized hero is loaded. If the character has already fulfilled the requirements for an achievement on another platform, the equivalent achievement should automatically unlock on the current platform.

Actual result

The character progress synchronizes correctly, but the corresponding achievement does not unlock. Because the mission or side quest is already marked as completed, it cannot normally be completed again with that character to trigger the achievement.

This can leave cross-platform players permanently unable to obtain certain achievements with their existing hero unless they create a new character and replay the game.