Pending manually triggered backups disappear after modifying a different plan's config

[nsubtil]

Describe the bug Modifying any plan config causes any pending manually-triggered backups for other plans to disappear.

To Reproduce

1. Create three backup plans, A, B and C
2. Trigger a manual backup for plan A
3. Trigger a manual backup for plan B, which will be left pending while the backup for A runs
4. Go to the settings page for plan C and click 'Submit'

Assuming the backup for plan A is still running, after step 4 the manually triggered backup for plan B is no longer in the queue.

Expected behavior Pending backup for plan B would still be in the queue

Screenshots Can provide if needed

Platform Info

• OS and Architecture: FreeBSD amd64
• Backrest Version: 1.7.2

Additional context Nothing comes to mind.