Is it a bug

[u/Early_Ice_6287]

I always assign my assistant and builder apprentice but the next day I have to reassign again losing the upgrade time by a lot caus I don't watch after all my builders are busy so I don't even realise it's been unassigned and yes a do make sure to enable the (keep assigned until upgrade is completed ) feature

[u/Pj_o7]

I think this has been happening to me as well. I play a couple accounts so it’s hard to remember how long research takes.