Re: Education bug? (enrollment drops to ~55%)
This bug has been exist from the release day. The problem is that some buildings stop producing kids and students. The maximum number of students is calculated based on the number of residence buildings you have. When some buildings doesn't produce students at all, the error occurs. Usually this bug appears when you have more schools than one. There has been several threads in Simcity forum considering this issue but I haven't ever seen that EA or Maxis has ever bothered to reply those threads.
You can temporary fix this issue by removing the bugged buildings during the school day.
Anyway, this is very known bug and it's called as ghost town phenomenon. This includes phantom students, phantom barbage, phantom recycling bins, phantom criminals, phantom homeless sims etc...
I think they won't ever fix this bug but maybe we can get another expansion soon and more regions instead!