OpenVPN Client Connection through existing OpenVPN Router Connection causes disconnect

[Viktor Jaep]

Wanted to please get your feedback to understand why I encounter this particular behavior:

Setup:
- Router is connected to OpenVPN provider, routing inbound/outbound internet traffic for entire household on the "Home LAN".
- Laptop (on the "Home LAN") is attempting to make another OpenVPN connection to a different OpenVPN provider, while from within the household network

Diagram:
Internet <--> VPN Provider <--> VPN tunnel/Internet <--> Router (OpenVPN) <--> Home LAN (all traffic routed through VPN) <--> Laptop w/ Separate OpenVPN Client

Problem:
If I initiate a separate OpenVPN connection from my laptop while on the Home LAN, which is already being tunneled through an existing OpenVPN connection established by the router, then the VPN connection on the router will frequently break and disconnect. I'd say it does this about 75% of the time. The other 25% of the time, the VPN tunnel established by the router will hold, while my laptop creates another OpenVPN tunnel through it, to a different VPN provider.

Question:
I'd love to understand (or get your opinion) as to why the VPN tunnel that was established by the router breaks when introducing another OpenVPN tunnel through it. Is there some sort of event or handshake that occurs that might be bleeding over to the main OpenVPN connection that causes it to think the connection was interrupted? If that's the case, then why is it that it can maintain a connection (at times), and am successfully running an OpenVPN tunnel through an existing OpenVPN tunnel that is being maintained by the router itself?

This is one of those things that has been nagging me for years... and would love to get some closure before 2025 starts.