Autocomplete box display issue

Sometimes the autocomplete box is so small it appears as just a grey line (see attachment– line of text I was typing is highlighted and autocomplete "box" is circled in red)

I don't know exactly what is causing the issue because I can't replicate it and it doesn't happen all the time.

autocomplete pycharm.png
Please describe the code and the steps that expose the problem if you will be able to reproduce it later.