Interesting : Bitcoin ABC try to fork ... the Bitcoin Blockchain.

[Meuh6879]

Before this date, no errors from this ABC clients ... All ABC clients generate the same error.
And then, be banned after a couple ... of attempt. 

[Foxpup]

The culprit is block #478577 on the Bitmain Crash chain, the first block after their new, untested difficulty adjustment mechanism kicked in. My Tor node saw this block five times today, and since it can't ban anyone I expect to see a lot of similar errors before the Bitmain Crash developers (if they can so be called) figure out that trying to connect to Bitcoin nodes after the fork isn't going to work.

Code:

2017-08-03 04:36:00 receive version message: /BUCash:1.1.0(EB16; AD12)/: version 80002, blocks=478579, us=[scrubbed].onion:8333, peer=1382
2017-08-03 04:36:00 AdvertiseLocal: advertising address [scrubbed].onion:8333
2017-08-03 04:36:01 ERROR: AcceptBlockHeader: Consensus::ContextualCheckBlockHeader: 000000000000000000639be19a0123a1c99d9fef89f0b8ac055a77f4ef86ae3b, bad-diffbits, incorrect proof of work (code 16)
2017-08-03 04:36:01 Misbehaving: 127.0.0.1:58628 (0 -> 100) BAN THRESHOLD EXCEEDED
2017-08-03 04:36:01 ERROR: invalid header received
2017-08-03 04:36:01 ProcessMessages(headers, 4051 bytes) FAILED peer=1382
2017-08-03 04:36:01 Warning: not banning local peer 127.0.0.1:58628!