I’ve encountered this issue with Docker. They randomly assign an RFC1918 subnet for internal services, and occasionally, this subnet clashes with a genuine corporate network or IP address. This can be quite frustrating to troubleshoot, especially if you’re not involved in Docker networking on a daily basis.

I've also run into this issue a lot, especially in AWS when developers with less networking experience start randomly picking VPC subnets (why they were doing that is a whole 'nuther issue). They wonder why connectivity in docker on their ec2 hosts doesn't work, by default docker chooses 172.17/16 which seems to be a common choice for VPC subnets. Annoying, but a teachable moment nonetheless.