To reproduce:

1. Create form with a select_one question and one integer question
2. Give response labels values that are different from their XML values (e.g. label: High school value: 1
3. Deploy, collect data
4. View report and group data by the select_one question

Expected:

The integer question shows the correct labels for each response option of the select_one question in the first column (e.g. High school)

Instead:

The integer question shows the XML values (e.g. 1)

See screenshot of project (user tinokreutzer), which shows that labels are missing in the table of the first question (Score) but are displayed properly in the column headers second question.