I haven't been able to figure out a pattern for it, anyway, so it might not be just walls - but lately, I've been unable to build walls on certain hexes. I'm gonna keep track of the comm unit over time, to see if it isn't actually certain comm units - either way, sometimes wall building works, but sometimes not.

and repeated attempts on the same hex also don't work - and they don't use up the comms move or attack, so you can repeat as much as you want. after you click yes on the pop up button to confirm build, instead of the regular window that says you built it, you get an error page.

whats worse is that this problem actually eats gold - I've thrown away 4k gold now without realizing it (till after), just trying it over and over, thinking that maybe if I do it a different way, it will then work. but no, it doesn't work, no wall - but it still charges me for the wall on each attempt.

crap, thought this was the bugs section when I posted...

my bad.