So? Everyone knew about this bug for months in advance and the "developers" (if they can so be called) never fixed it. Anyone who insists on using software known to be this incompetently developed deserves whatever they get, in my opinion.

The chainstates are incompatible. You will need to run Core with the -reindex-chainstate parameter to fix it. Don't ever run any two of SegWit2x, Bitcoin Cash, and Bitcoin Core with the same data directory. Nothing good will come of it.