This question always pop out in the forums and reddit and here’s my mini-guide to this issue.

Whenever people ask, the answer is yes. Troops will continue to upgrade while your lab building is upgrading.

Pictures:

Messed up my first picture, so this is the picture from the day before. See how both sf and lab still has one day left to upgrade. I did them both together so they’ll end together.

Once its done… Hey wtf?! Healers time didn’t move at all, why? It is actually a small visual bug, the troop is already done. Now you need to either restart the game or visit someone else’s base or go to raid. (Basically, you need to look away from your village, your lab is shy) Once that’s done:

Bam. Healers only have 32seconds left, ready to put archers into lab!

Hope this guide has helped players. Some people unknowingly at step 2 get enraged and gem their lab, NEVER DO THAT! Its just a small visual bug and don’t think it doesn’t work.