I think this is a bug.. but there's a few invisible spots around Swamptown that locks your character in one spot, so you get stuck and can't move forward. It also disables your mount, so the only thing you can really do is spin around until it eventually lets you go... just to end up getting stuck in a nearby spot again.
On another note, another possible bug that I came across today was from the blob. I ended up getting two slime spoils(green & golden), but when I tried equipping the golden spoil, it didn't work. I'm not sure if anyone else is experiencing the same thing but the item is still in my inventory, and it shows that I have it equipped(on my profile) but once I leave my profile to go back to the game screen, it removes the button so I can't even have a way of "opening" it.. Which then leaves 1 item button on the right side of my screen until I switch out the golden slime spoil to another item.