Mixed languages in Try Demo Mode

(This was tested with elementaryos-6.0-daily.20210503)

**Describe the bug**
I get mixed languages (English, Bulgarian) in various settings plugs in the Try Demo Mode after clicking Language & Region (without changing anything).

**To Reproduce**
Steps to reproduce the behavior:
1. Choose Try Demo Mode in the new installer, choose English as (system) language.
2. Once the desktop is loaded, go to Settings
2. Click on one of the plugs: all labels should be in English.
3. Go back to All Settings
4. Click on Language & Region
5. Notice that the default Region says Australia and Formats says Bulgaria
6. Go back to All Settings again
7. Now click on one of the plugs again. The labels are now in mixed English and Bulgarian.

**Expected behavior**
The language for the labels should still be English.

**Screenshots**

**Additional context**
What could be worth mentioning is that I chose Swedish keyboard layout in the installer since that is what my laptop has.