Many of my programs behave this way on my Windows machine (Chrome, calibre, Komodo Edit, etc...). Big delay/grind on the first launch after boot up (regardless of how much time has passed since boot) with speedy subsequent launches thereafter. Just figured that was "the way things were" with some programs.
Granted; it's not
minutes, mind you. But it is a considerable delay. That's why I never reboot my Windows machine if I can help it.