I am currently experiencing a "flipping interfaces" problem on a VMware-based virtual machine running Funtoo. I have tracked it down to the following udev rule:

The /lib64/udev/rules.d/75-persistent-net-generator.rules files currently has the following lines in it:

# ignore KVM virtual interfaces
ENV{MATCHADDR}=="52:54:00:*", GOTO="persistent_net_generator_end"
# ignore VMWare virtual interfaces
ENV{MATCHADDR}=="00:0c:29:*|00:50:56:*", GOTO="persistent_net_generator_end"
# ignore Hyper-V virtual interfaces
ENV{MATCHADDR}=="00:15:5d:*", GOTO="persistent_net_generator_end"

This causes VMware virtual machines with more than one network interface to not have consistent ordering of interfaces – so for example, eth0 and eth1 will swap randomly upon every reboot. I am experiencing this issue and it is causing network interfaces to mess up.

Ideally, this would not happen as having network interfaces swap is a bad thing. I am not sure of the rationale for these udev rules but they seem incorrect. 

References:

https://kb.vmware.com/s/article/1024025 - explanation of how MAC addresses are generated on VMware vCenter Server and vSphere Hypervisor (ESXi). See esxcfg-info command information in this KB article.