Please post a bug report in the official Adobe feedback forum: Lightroom Classic CC | Photoshop Family Customer Community . Be sure to include all the output from the menu command Help > System Info. Adobe product developers and senior technical support read every post in that forum, but not here.
Meanwhile, some troubleshooting steps that might produce a usable workaround:
- Try disabling the GPU (or enabling it, if it's off) by checking/unchecking Preferences > Performance > Use Graphics Processor.
- Try running LR in another language via Preferences > General > Language (restart LR after changing it). A long time ago there was a similar bug that only afflicted some languages.
- Update your Mac to the latest version of Macos (10.13.3) -- that's the only way to get the latest graphics drivers. LR tends to trip over bugs in older graphics drivers.