Yes it freezes and has laggs at mine too, it usually appears whenever there's happening 'much' at the Seachart, especcially when there are much ships in the chart, alot of shooting etc etc.
Probably always you can see that when you try to change the map and hold the {return} key*, you'll see the Golem sends multiple Map Change Requests, there's lagg in changing the maps. Also lagg when there's happening 'much' and when sailing the maps, when you click the map you'll notice a slightly increase in time before it's going to set sail.
I hope I gave you enough details, don't hestitate to ask.
*Changing to map using the return key, try holding it and you'll see multiple requests sent