I ran into this problem a long time ago with EKS. I picked a network for EKS, but it also needed a network for docker running on each node, and this happened to conflict with a network that we had peered to AWS (we were an ISP, this was our internal management network).
I learned on that day to put everything in our IP address management system (netbox). Allocate private networks like we allocated public networks to our customers. (It would have been nice if I allocated Docker's defaults before they had been allocated to an internal network, but ... hindsight 20/20. At least with that network in the IPAM system, people could figure out why it broke though.)
I have had this happen with Docker compose too in a much less complicated setup.
When you add a network, it gives you a network. It allocates a pretty big address space each time, and eventually it'll run out of 172.16.0.0/12 space and move on to 192.168.0.0/16 networks.
Why can I get to this from the guest network but not the client network? Oh...
It sucks, but I manually set networks now. And keep track of them.
Ah what a fun issue to figure out and resolve 10 minutes before endofday,especially if you are the one handling docker and some dude in another country is handling the vpn that wants access to said docker.
