I just downloaded the December 1.hmi, and recompiled it both for basic and enhanced 5" screen. Compilation successful. Got one warning on an overlap of a component on factoryrecover (that I don't remember), but other than that no problems.
I am running v0.53 of the Nextion editor. Any chance you have something different?
BTW: The "December" version fixes the "9" character in the manual frequency entry that should have been a "0"