I believe there to be a bug when loading back saved games.
It seems to be with the Garrisons.
For example I have only tested and found it out when playing in Skirmish.
This is what I found out.
A Garrison to me seems to when switched on, protect your walls for example by giving them a 36% explosion protection from Bombards. So if you had a wall with 300hp, and the AI set off a Bombard, the hp of the walls would lower down to 238hp, because of the Garrison.
Without a Garrison it would of dropped down to 175hp the wall.
Now when you load back a saved game with the same Garrison that was originally switched on.
It loads back the saved game, and the Garrison still shows as it's switched on.
But the Garrison protection of the wall isn't 36% anymore. The hp dropped down to 175hp when a bombard went off when the Garrison was on, with no effect from the Garrison.
I have to sell the Garrison and re-create it and switch it on again to get it to work again after loading back a saved game file.
Customer support service by UserEcho