On the experimental build 0.9.6.38
The building preview in red or blue won't update if there were changes in amount of supplies in the base - for example when there is lower amount of supplies and you can't build the building - it stays blue, the other way around as well - someone resupplied the base with building mode on and the building stays red - the only way to "redraw" it is getting close to it, then it's fixed