Just for whoever may be looking for this information : i’ve upgraded from 10.14.4 (clover 4920) to 10.14.5 without anything to do or to reinstall about EFI/clover (= just by using the system upgrade from Mojave). Took 20 minutes.
macOS Mojave 10.14.6 (Clover R4982) work fine
macOS Catalina 10.15 Developer preview 4 (Clover R5050) work fine
macOS Catalina 10.15 Developer Preview 5/6/7 and Public Beta 4/5/6 don’t work