This issue affects all languages. It is not specific to PicBasic Pro.
It only affects the Enhanced core devices (12F1xxx and 16F1xxx).

Programs are compiled correctly, but non-critical messages are reported.

Those messages can be supressed with ...
Code:
#HEADER
  errorlevel -303  ; suppress Program word too large
#ENDHEADER
Hopefully Microchip will fix it.
If not, PBP will need to suppress it by default.