Is oligarchy form of goverment bugged?

Hi,

I recently tried oligarchy. but extra trading range seems to not work properly. I see trade offers from expected radious, but when I try to buy, I get error message stating only "Error!". I have enough ships and enough gold. I attach some screenshots. One with the error message and the other two where I marked which trade offers work and which do not.

I have a theory that in order for the trade to be possible, the distance still can't exceed the level of the trading post.