Time Machine removes APFS Quota silently from APFS Volume

Originator:joe
Number:rdar://FB11747065 Date Originated:11/02/2022
Status:Open Resolved:
Product:macOS Product Version:13.0 (22A380)
Classification: Reproducible:Yes
 
When upgrading from macOS Monterey to macOS Ventura, I noticed my Time Machine volume’s APFS quota was missing. I created a new APFS volume with a 1TB APFS Quota, configured Time Machine to use this new volume, and the quota was once again removed. I have attached a screen recording showing the issue being reproduced at will.

Expected Result: Time Machine uses APFS volume with quota without modification, as previously with Monterey and Big Sur releases of macOS. 

Actual Result: When adding the volume to the Time Machine configuration and starting a backup, Time Machine removes the APFS volume quota silently.

Steps to reproduce:
1. Create APFS volume with a quota for Time Machine: diskutil apfs addVolume disk5 APFSX NewTimeMachine -quota 1024g -role T
2. Verify volume was created showing quota using diskutil apfs list
3. Open System Settings
4. Navigate to General, then Time Machine
5. Add NewTimeMachine volume to Time Machine configuration. Note that the UI shows both available space and the quota
6. Wait for backup to start in 60 seconds, or manually start by Control-Clicking on the volume
7. When UI changes from “Connecting to backup disk…” to “Preparing to back up,” observe the UI change from showing “1.02 TB available, 1.02 TB quota” to “3.62 TB available” in attached video
8. Verify that the quota has been removed from the APFS volume using the command: diskutil apfs list
9. Confirm the quota has been removed using Disk Utility

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