What causes the delay on changing icons on the taskbar?

Hey,
So I've got some pinned icons on my Win 10 taskbar, such as Chrome, Notepad++, file explorer etc.

I go to change the Chrome icon and it doesn't change on the taskbar like it did with W7. But sometime later, unsure when, could have been after a restart or after waking up from sleep or just a time period later, it finally changed to the icon that I'd chosen.

I did this to file explorer as well and some time later it finally changed to the icon that I've chosen for it.

1. Why is there this delay?
2. What if anything can I do to avoid the delay and get the icons to change immediately as they did with Windows 7?

Thanks

Can you tell more about that, when the icon not change, what color is it ? And how long it take to change and also some information about your PC because I know it depend on your hardware than software

It seems that it takes hours or more for it to finally get around to changing. The icon that I'm talking about is the standard Google Chrome icon, I change it to one of the alternative Chrome icons that are located in the chrome exe file and it doesn't change instantly like it does in Windows 7. As I said, it could be changing after a reboot, or after coming out of sleep, or just maybe 2 hours or 24 hours later for all I know.

It's not a color change, it's using an alternative icon for the pinned programs on the taskbar in Windows 10 that is a problem.

My system specs are located in "My System Specs" listed on each of my posts.

Honestly, if changing a pinned program icon on my taskbar is more dependent on my hardware than the software then Microsoft has got a long way to go in optimizing Windows 10 as my hardware is more than capable of doing such a menial task when it can run most of today's and yesterday's games at 60+ fps.