They user agent name sounds like an unsynchronized bitcoin cash node back from when they could still connect to bitcoin nodes (CMIIW but I believe there was a timeframe when BCH nodes could connect to BTC nodes before a BIP was rolled out that prevented this?), maybe they defined a bunch of flags that are unrecognized in bitcoin. But the height doesn't correspond, but even then we know that someone had to have forked Bitcoin core to add those extra flags.
As far as I can tell there is no code in bitcoin core that blocks connection based on user-agent. There was a optional patch back in 2017 that people could use to block certain ones if they chose to IIRC.That is irrelevant here since any of those fork-coins start from blocks in 2017 (height 500k maybe), this was a fake block in early days (height <20k).
