What kind of problems do you genuinely have with a dynamic language/duck typing? Like, that you've actually experienced and said "You know, I'm not saying this

What kind of problems do you genuinely have with a dynamic language/duck typing? Like, that you've actually experienced and said "You know, I'm not saying this just because I'm not used to it. This bit right here is a design flaw". This is such a tired and boring argument by this point, but I'm willing to entertain it because duck typing is at the bottom of my list of worries.