I'm still working towards the "Industry" achievement: upgrade 100 buildings to level 5.
During this event, I bought some grout and started upgrading 2 mills and a bakery to level 6.
To my surprise, once those upgrades were completed, the buildings no longer counted towards the achievement.
I admit they're no longer level 5, but really ? That can't be a desired effect.
I hope this get fixed soon. In the meantime I'll certainly wait with further upgrades to level 6 until the bug is fixed or I have my achievement, whatever comes first