Originally Posted by StuckInYYZ

Foreign commercial VPNs (eg, Nord, PIA, Express) are hit and miss due to the whack-a-mole game played between the data provider and the VPN. The VPN companies are constantly changing their access points within China and the providers need to scan their networks for those access points, confirm they're from those commercial VPNs and then block them. As they don't want your block list to be inaccurate, they release those IPs back into the wild when they confirm they're no longer being used for VPN traffic. You might currently have unblocked VPN access, but that can change very quickly and without warning.