Bifrost tile is inaccessible for military and scouts

I started the 3rd level of my Bifrost as the Eagle. By 803, I realized that the tile containing the Bifrost seemed surrounded by rocks and was inaccessible. I tried selecting my military and my falconers separately, but neither type had access to the Bifrost tile. I was completely unable to walk into the tile, making it impossible to clear or scout. Each time I tried to approach, the mouse showed the red X.

Windows 10, DirectX, Solo Bifrost using North American server

N_G_zy2jyu.png

NG_game_info_igqyl5.png