When you tunnel/encapsulate your traffic, many variables change at the same time, such as:

- maximum transmission unit (MTU)

- TCP maximum segment size (MSS)

- different DNS responses leading to different edge servers

- TCP reordering, which may now occur on the tunnel layer

- lost packet retransmission, which may now occur on the tunnel layer

- time to live (TTL) hop count on the packet

- IPv4 may be used for some connections that were previously using IPv6, as some VPN services are IPv4-only

- different peering between the VPN server and the edge server

ISP traffic categorization is only one variable.