Module grades don't work for modules where the assignment name starts with a number

For some of our modules, the module export showed no grades (neither passed nor failed). For example https://submit.tudelft.nl/module/661 did not show grades.

In the grading formula test it says invalid formula, but the formula just contains the only item in the module.

The problem seems to be the assignment name starting with 10, as only the modules where this is the case have this issue. Renaming the assignment to something that starts with a letter and changing the formula to match fixes the issue (which is what we did as a workaround).