Yeah, and even before that BB was running around on a raft and Shanks instead of pursuing him went to be WB not to let Ace go after him.
I don’t think it’s that bad a mistake from Odas part
If we rationalize too much almost all manga/anime had flaws, PIS, people could t have been more, smarter choices, etc etc
Oda was developing his story and his main villain, obviously he wouldnt make Shanks going for the kill and chasing Teach
instead he gave us the great moment with WB and the cloud clash, Banaro island, Teach chasing Luffy and Jaya speech, Shishibukai Teach and Marineford
it did built a great villain
Im ready to sacrifice a little bit of coherence or brain to have all that as a reader
I think you have to make your mind that Shanks couldn’t beat/chase Teach or try to cope with a reasonable excuse
when you’re a teen/kid/young adult and you’re reading OP and you’re reading/watching pre skip for the first time I dont think it matters at all that Shanks didn’t go for Teach himself