With the recent git master and after I had deleted my old kdenliveui.rc the monitors don't show any (enabled) overlays anymore. In addition, the monitor context/hamburger menus have lost all options for showing/hiding overlays, except for overlay audio waveform. Reproducible: Always
Yes, that was due a bug deleting some interface actions when customizing the toolbars. However everything goes back to normal if you restart Kdenlive. I have now fixed the monitor context menu to not loose its options, but there might be other menus / actions disappearing, let me know if you encounter further problems.
Seems to be fixed now, so I'm closing this bug report. Thank you very much for quickly fixing it, Jean-Baptiste!