Fontwarning for vertical metrics

Hi, I installed Penpot on Ubuntu for myself, but every time I upload fonts for a project, I get the following warning:

We have detected a potential issue with your fonts relating to vertical metrics on different operating systems. You can use online services like this to verify this. We also recommend using Transfonter to generate web fonts and resolve issues.

I translated it from German, so it may differ slightly in reality. I haven’t changed the fonts, so it’s basically a problem, and I can’t tell if it causes any real problems. Does anyone have experience with this problem?

Best