Ohh I had the same/similar thing happen a while ago...
-it affects only max level guilds (they get 2 military command points with the last upgrade, and only one of those points seems to work)
-only the
very last command point doesn't work
-doesn't matter which specific command it is (support, control, sabotage, fortify..). So it should be an issue with the point and not a specific command
-no error message (usually we get an ordinary new arrow.. in this case just nothing happens, like server just drops the request)
Perhaps helpful?
(can someone from RG confirm they can't set ANY commands with the last point.?)