Noticed this issue with mass construction achievement this morning; Let us know if you have the same thing with mass contruction and/or different achievements. Haven't checked them all yet.
Screenshot when I compared
Screenshot when guildmate compared
Screenshot of achievement in my achievement book also not right
Several other guildmates were also reporting only 11 achievements for this section.
UPDATE: It would appear that there is at least 2 in the military section that appear later too - 1 in generals and 1 in troops