Character no longer moving after 4.8.x update

OS: Windows 7 x64

I just recently updated a project to 4.8.1 from 4.7. I’ve been using the same movement BPs for a few major versions now, but suddenly, “Add Movement Input” isn’t working on a character.

The player controls their body as one character, and that body drives a remote controlled avatar (another character-derived BP). On play, the body spawns the avatar, spawns a player controller, and has the new controller possess the avatar. Every tick, the body character calls a function on the avatar to provide input, which is then used in the “Add Movement Input” function. I’ve printed the world direction that’s being passed to the function after the Set Actor Rotation node seen in the screenshot below, and it seems to be working fine. In fact, the avatar does rotate as expected. However, it doesn’t move. It doesn’t even fall when spawned very high. I’ve reviewed the modified properties on the avatar’s character movement component and don’t see anything suspicious.

I have no idea what’s going on at this point. Any suggestions would be appreciated, and I can send my project (which is about 500 MB compressed and 2 GB extracted) to staff if absolutely necessary.

I solved this by spawning an AIController instead of a Player Controller. Apparently, two player controllers no longer play nice.