Font type in Sheet Tab changed

Hi there,

some weeks ago my Libreoffice ( on a macOS Mojabe (10.14.1) started to show some strange font in some places. The most primary one is the sheet tab names in Calc. When the sheet is active the font in the name tab change to another one that is illegible. When is not active it uses the normal font type that is legible [1st Image]. Also some titles in the pop-ups within the app are also in this strange font [2nd Image]. Here are some examples:

1st Image

Sheet Tab Name

2nd Image

Pop-up from LO

I haven’t changed anything in the application and already restarted LO in the Rescue Mode but the problem persisted. The next step was to delete and reinstall the application, but the problem is still there.

Anyone has an idea what can I do to resolve this?