This Issue is Very Specific to the French User due to French Standard Translation, during Migration Activities.
Reproducing the Issue
1. Go to Business Configuration work center
2. Select Implementation Projects
3. Search for Migration of XYZ
4. Migrate XYZ using the Migration Tools
5. Select You Can Also, Adapt Migration Object
6. Download Migration Template
7. Save The Template and Open Template
The Header Name of Each Sheet (as listed in the last template sheet) are Being Used to Make up the Sheet Labels that you Have in the Template File When Opening it in Excel. Now These Sheet Labels can Only Have 31 Characters.
If the Sheet Header is Longer Than 31 Characters, Then it is Simply cut Automatically at the 31st Character When the Template is Being Generated.
As Long as the Abbreviated Label Names (First 31 Characters) are Still UNIQUE , This Will Work.
Customer Will Have to Manually Create a File With Modified Labels. As for the Upload not the Actual Label Name is Relevant, but the Technical Sheet Name Which you find in the Hidden Line 4 or 5 Sometimes.
KBA , SRD-CC , Cross Components , Product Enhancement