BUGFIX: Allow updating of entities related to value objects after persisting

[fcool]

Fixes #2870

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Checklist

• [x] Code follows the PSR-2 coding style
• [x] Tests have been created, run and adjusted as needed
• [x] The PR is created against the lowest maintained branch
• [ ] Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• [ ] Reviewer - The first section explains the change briefly for change-logs
• [ ] Reviewer - Breaking Changes are marked wit !!! and have upgrade-instructions