When you place pylon it may not work

[grechnevi]

Player places pylon, then this player don't see it. Other players can see it but can't interact and use it.
Same player can see this pylon after re-login but can't interact and use it.

If the player places pylon two times (so gold cost = x2) on the same spot, then this pylon does work.

[hakusaro]

This is a known issue -- we're working on it in: #1795.