I agree that this bug is more complex than @Marcos described but I got this issue even if I didn't use VPN (but I have 2 VPN clients if it is important it is OpenVPN Connect and Check Point). I've tried system temp folder and cache cleanup and turning on pre-release updates like was suggested here but it didn't help I've got this bug once more after that. I can't say if it became rarer now because there was no situation which requires me to turn the firewall off.
I've tried to turn it off just to test if the issue still happens but it had not happened, however, it does not mean that it is solved because:
1. It happened once after I was done cleanup/update settings.
2. Previously it happened in 2 case sets: when I start having problems with DNS resolution for an unknown reason (turning off firewall helped, it looks like FW disabled windows DNS cache connectivity for some reason) and when some program had connectivity issues (to test if it is related to firewall).
3. I've worked with several programs that actively used internet and with a browser for a few hours with firewall disabled before turning it on again.
If it is important I have 202 rules right now (some of them were imported from settings file, some were created using Remember permanently option in firewall popup and some of them were created manually).
If it is important I have 2 internet providers: router automatically swap to the secondary connection if the primary connection fails.