Bugzilla

**Found in**
* Nightly 138.0a1 (2023-08-25)
 
**Affected versions**
* Nightly 138.0a1 (2023-08-25)
* Beta 137.0b11

**Affected platforms**
* All

**Steps to reproduce**
1. Create a few Tab groups and close Firefox.
2. Start Firefox in offline mode.
3. Restore previous session while in offline mode
4. Open the list all tabs menu.

**Expected result**
* There should only be 1 of each created Tab groups.

**Actual result**
* Each tab group is duplicated after restoring the previous session in Offline mode.
Please note that this issue does not occur with normal mode.

**Regression range**
Not Applicable

**Found in**
* Nightly 138.0a1 (2023-08-25)
 
**Affected versions**
* Nightly 139.0a1 (2025-04-17)
* Nightly 138.0a1 (2023-08-25)
* Beta 137.0b11

**Affected platforms**
* All

**Steps to reproduce**
1. Create a few Tab groups and close Firefox.
2. Start Firefox in offline mode or normal mode.
3. Restore the previous session.
4. Open the list all tabs menu.

**Expected result**
* There should only be 1 of each created Tab groups.

**Actual result**
* Each tab group is duplicated after restoring the previous session in Offline or normal Browsing mode.

**Regression range**
I will update with a regression range as soon as possible.