Here’s a sample chart with pretty long labels. The labels are long because they are complicated and can’t really be shortened effectively. For a “question and answer” type chart, answers often will be longer than 10-20 characters. (Many of the labels also start the same way, because this was a multiple-choice type item, and one of the answers selected was the same, and it does not seem this situation is supported in the charts, either.)
Suggestion: Enable text wrapping (and other text formatting features) for chart labels.