This is a well known problem with RIMMSqol that has been fixed through a settings dialogue.

RIMMSqol does a refresh of UI elements as part of it's UI modification abilities, however due to the way More Planning is loaded it's UI elements can only be refreshed by restarting the game.

This is not a fault of RIMMSqol or More Planning, just an issue caused by one of RIMMSqol's features colliding with More Planning.

How to Fix

Originally posted by Razuhl:

Avoid Designator Refresh

In the mod menu settings under the general category is an option to avoid the refreshing of architect buttons. Some mods(e.g. AllowTool mods) use custom buttons that are not reloaded when vanilla buttons reload.
Those buttons will vanish, until a restart takes place, when changing anything in the mod menu. Once you are done with changing the architect buttons it is useful to activate this setting to avoid the problem.