4CC was in Taipei in 2014, 2016 and 2018. All had Chinese competitors (indeed, all had Chinese medalists!)As I've seen such rumor mostly from FS forums in China, I'd suggest to wait until the entry list to JWC published to make any judgement on this.
BTW, Taipei Government doesn't have the right to issue VISA for any visitor from China; it should be the specified agency under Taiwan Government. (Actually, I highly doubt Taiwan's government would refuse to issue the VISA to competitors from China for such international competition. But I won't be surprised that China's government REFUSEs to send their skaters to Taiwan given some meaningless political excuse ...)