I assume this is a reference to SpiceJet wet-leasing Czech 737s, although Smartwings (or historically Travel Service) livery probably should’ve been used, as they’re the ones who have leased their aircraft to SpiceJet, while ČSA themselves haven’t (as far as I know).
I believe its more likely due to the use of the PRG hanger in the generic build. Doesn’t bother me personally as I understand the intention but could be repainted for each airport that is added as generic as a local airline. Does likely mean a lot of extra work though.