Booting Windows 10 from OpenCore 0.6.2 creates a minute long pause with black screen in the middle of Windows boot

Hello, I am dual booting Catalina and Windows 10 from OpenCore 0.6.2, and recently (with either Windows 10 update or OC 0.6.2?) a long pause started to appear in Windows 10 boot.

What happens is:

1. I choose Windows in OpenCore boot menu
2. Windows shows Windows logo and loading dots
3. after a second or two a screen goes blank, and computer does seemingly nothing for about a minute or more
4. then a screen comes up, and Windows boot continues, and Windows boot normally

Any idea what is causing the delay?

I can open BIOS, and do 'boot override' to boot directly from Windows 10 UEFI partition, and that boots Windows 10 almost instantly, but I'd love to be able to use OC boot menu, and not complicate things further with rEFInd and etc. chainloading (I already have 2 SSDs, one with Catalina + OC EFI, second with Windows and their EFI bootloader, so I'd need a third one just for rEFInd).

I have Haswell desktop hackintosh (i7-4790) with RX580, if that helps.