Bug: WAN PPPoE to DHCP (with workaround)

[BennTech]

I was at a client's the other day updating their pfSense box to 2.1.4 and changing their WAN from PPPoE to DHCP.  PPPoE to DHCP should be a simple change, but instead I got the following error:

The following input errors were detected: You have to reassign the interface to be able to configure as dhcp

I tried reassigning interfaces and swapping cables to no avail.

However, what did work was to first assign the WAN from PPPoE to static and apply, and then change static to DHCP.

Can't provide any additional troubleshooting as I don't visit that client regularly, nor do I have a spare pfSense box hooked up right now.  Just wanted to post the easy workaround for those who encounter this problem.