### **Environment**:

Your OpenProject Version: 12.1.6

Operating System / Browser / OpenProject language:

### **Steps to reproduce:**

1. set "First week in year contains" to "Thursday" (German version)
2. set User's interface language to English
3. enable Gantt (calendar weeks visible)

### **Actual Behavior**

Current week is not German one.

### **Expected Behavior**

Respected settings "First week in year contains".

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