Have seen it in EB. Wall was full repaired(i reparied wall to max 5 min before upgrade) and get zero after upgrade.
Wall beside was repaired to 50% but after upgrade it was o to.
Can have something to do with a part of wall that isnt fully reparied, even missing 1 suply it will after upgrade to heart of throne not be fully upgraded, only stands with 0 hp.
(Terms of ?? is to long and come over and over again. Dont say anything what have be changed. Don know if anything is changed, Its not readable. Have accepted it once and know i dont get mone back if i dont fill it in. I say i dont accept anyway)