Banners cause disconnect from realms

So I just started fiddling with banners in my Realm, and some weird stuff started happening. First I'd go to place one on the wall, and everything seemed fine. But then I decided I wanted to move it. I tried to take it down, but shortly after breaking it I was disconnected from the Realm entirely. It took several attempts to reconnect, getting the "Unable to connect" error several times, like I was having connectivity issues or something. When I finally was able to get back on, things got even weirder. The banner I put was still on the wall, and I also still had one in my inventory. Breaking the one on the wall only made me disconnect again. Also the one time I did succefully break down a banner without disconnecting, it also came away with some weird item that had the icon for the sign, but when i place it it became a black banner that seems to not have any collision, but i can't place any block over it or try to remove it.