Extended tips tend to hold longer text. Windows, at least, breaks it nicely into two lines but Qt shows the tip as one long line making it difficult to read.
Should have recently been fixed by Rafael. (But your bug report lacks information on what version you're using, so please reopen and add more details, including exact steps to reproduce and a screenshot if you still see the issue.) *** This bug has been marked as a duplicate of bug 162297 ***
Reported for Fresh, and confirm the improvement for master.