Bugzilla

**Affected versions**
* latest Nightly 101.0a1
* Beta 100.0b4

**Affected platforms**
* Win 10 x64
* Ubuntu 18.04 x64
* macOS 11

**Steps to reproduce**
1. Launch Firefox on a profile A.
2. Launch a second instance of Firefox on a profile B.
3. In one of the browsers, from `about:preferences`, "Language" section , change the language to a difference one than default (e.g. Italian).
4. Perform a sync to both instances of Firefox.

**Expected result**
* The languages are synced between the Firefox profiles. 

**Actual result**
* The languages are not synced between the Firefox profiles. 

**Suggested Severity**
* S2, since the users will lose their language settings after syncing between accounts. 

**Regression range**
* Not a regression, more like an implementation bug, since it can be reproduced after Live language reloading feature was implemented.
* The issue cannot be reproduce on Release 99.0.1, where the above feature is not landed yet.

**Affected versions**
* latest Nightly 101.0a1
* Beta 100.0b4

**Affected platforms**
* Win 10 x64
* Ubuntu 18.04 x64
* macOS 11

**Steps to reproduce**
1. Launch Firefox on a profile A.
2. Launch a second instance of Firefox on a profile B.
3. In one of the browsers, from `about:preferences`, "Language" section , change the language to a difference one than default (e.g. Italian).
4. Perform a sync to both instances of Firefox.

**Expected result**
* The languages are synced between the Firefox profiles. 

**Actual result**
* The languages are not synced between the Firefox profiles. 

**Regression range**
* Not a regression, more like an implementation bug, since it can be reproduced after Live language reloading feature was implemented.
* The issue cannot be reproduce on Release 99.0.1, where the above feature is not landed yet.

**Affected versions**
* latest Nightly 101.0a1
* Beta 100.0b4

**Affected platforms**
* Win 10 x64
* Ubuntu 18.04 x64
* macOS 11

**Steps to reproduce**
1. Launch Firefox on a profile A.
2. Launch a second instance of Firefox on a profile B.
3. In one of the browsers, from `about:preferences`, "Language" section , change the language to a difference one than default (e.g. Italian).
4. Perform a sync to both instances of Firefox.

**Expected result**
* The languages are synced between the Firefox profiles. 

**Actual result**
* The languages are not synced between the Firefox profiles. 

**Regression range**
* Not a regression, more like an implementation bug, since it can be reproduced after Live language reloading feature was implemented.
* The issue cannot be reproduce on Release 99.0.1, where the above feature is not landed yet.
* This issue can be reproduced with some of the most used languages: en-US, de-DE,  fr-FR and zh-CN.

**Affected versions**
* latest Nightly 101.0a1
* Beta 100.0b4

**Affected platforms**
* Win 10 x64
* Ubuntu 18.04 x64
* macOS 11

**Steps to reproduce**
1. Launch Firefox on a profile A.
2. Launch a second instance of Firefox on a profile B.
3. In one of the browsers, from `about:preferences`, "Language" section , change the language to a difference one than default (e.g. Italian).
4. Perform a sync to both instances of Firefox.

**Expected result**
* The languages are synced between the Firefox profiles. 

**Actual result**
* The languages are not synced between the Firefox profiles. 

**Regression range**
* Not a regression, more like an implementation bug, since it can be reproduced after Live language reloading feature was implemented.
* The issue cannot be reproduce on Release 99.0.1, where the above feature is not landed yet.

**Additional notes**
-  This issue can be reproduced with some of the most used languages: en-US, de-DE,  fr-FR and zh-CN.