I assume this is a well-known bug, so if it has been posted before, my bad.
In Infinitum before the SOR, I went ahead and put in my build order for the HW. The planet was 250 size with 10 farms already built. However, I was still able to order 250 new buildings – 10 more than should’ve been allowed. Apparently, the farms aren’t properly accounted for at SOR.
This isn’t a bug. 240 max size 10 are overbuilt.
Mine shows as 250 Max Size.
This is working as expected.
250 planet size, 10 existing buildings.
The rule that came in to stop flint jumps is that you can build(in queue) the max of the planet size or number of buildings already built.
Ah, ok. Not that eco jumps really got stopped much though. 
Make mw instant and all those ridiculous jumps will be impossible.
Yeah now players have found a new method.
The new jump method has much more risk than the flint jumps, as you have to transfer ownership of the planets losing the portals putting you at risk of raids etc has costs in sending fleets and have to wait for transfer times etc.
Still i would like to see them removed, as they give an organised/active family an even greater advantage.
As @The_LiGhTgUnS said making the NW apply instantly would be a way of preventing the current method.
Intra family attacks costing morale would lower the amount of abuse you can do with it as well.
Making you unable to overbuild planets the tick you take them could also work.