I found a significant bug and worked around it. I'm putting this here for documentation purposes. We may have other sideeffects of the root cause that is as-of-yet undetermined.
So I've tested this 1000 times. A few days ago(4/11/2018), in multiplayer clients were falling through the terrain. No changes around the timeframe seemed to account for it. I haven't found the root cause. The only indication I have is that the Client ShooterPlayerController cant seem to communicate to the TerrainManager. Or more precisely, it can, but the terrainmanager behaves like a client role when it does.
This was important for tracking client location. To work around it, I rewrote the code to track the player directly from server world data rather than client events. That frankly is better but doesn't explain why this stopped working. Or what else could be broken because of that issue.
|Looks like the Terrain problem may be new, MP for terrain has been working for years|
|In the Build as of 4/7/2018 The Client can connect to the server and generate terrain|
|Although ShooterController sends server call, it is heard on Role 1|