We are seeing this issue with our default theme of Essential, but it's also true in More and Academi. Interestingly, it does NOT appear to be a problem when using Archiaus.
Extremely long section names do not wrap when editing is OFF. They do wrap when editing is turned ON. Are others seeing this?
Also, anyone have a fix for Essential? I just updated to 3.1.0.8 (using Moodle 3.1.1) and that update did not address this issue.