Try this. Build a new map (in pak.Britain experimental), with timeline set to 1750. Check to make sure that some city built a Masonry bridge (cobblestone) over a river.
Look at the weight limits on each tile of the bridge. They are correct; all three have weight limits of 8.
Now save the game and reload. Look at the weight limits on the bridge again. They're wrong, causing all manner of trouble. The tile at one end has a weight limit of 12, while the other two have weight limits of 1.
This particular load/save corruption appears to exist only with city-owned bridges (it doesn' t happen to player-owned bridges), which is really strange. I haven't tested whether it only exists with bridges built on initial construction or whether it exists with "city expansion" bridges, but I'd guess both.
It's very bizarre and I haven't been able to track it down. (I put two small, safe patches into my jp-devel branch in a further attempt to fix this, but they don't fix the problem.)
I'd say this is top priority to fix before making another release. It's extremely annoying.
Thank you for the report - found and fixed.
Thanks!
Can't seem to pull the latest source from github. Zip gives a 0 byte file (?)
Hmm, very odd. A Github error, I suspect - try again a little later?