Bugged auto navigation

I've started to notice that sometimes auto navigation goes into an infinite loop of turning. That is, instead of sailing in a straight line, it makes microturns, barely visible by the naked eye, all the time. And when I disable auto sailing, it immediately starts to sail 2-4 times faster. This is especially common on a way out of Venice. I think this might be related to the composition of my fleet, the lead ship, or maybe some bonus effects... Has anyone had this issue also? I've never had this before.