Had a fun run-in with ya @bobotov. The whole time I was trying to block the IP through ufw or IPTables, that didn't work for whatever reason.
I feel like Sourcebans++'s SourceSleuth should have done a bit of checking (since sm_banip does work and your IP was correctly added to the DB) and at least kicked. addip from the server console didn't work, that might just be me rusty with it though.