Gateway DNS bug

[cmb991]

https://docs.opnsense.org/manual/how-tos/multiwan.html
Step 3 says System > Settings > General
Assign a DNS server to each Gateway (or two DNS servers)

Well when I put 1.1.1.1 in the box and select my WAN1 connection, it saves the 1.1.1.1 but doesn't save WAN1.  It changes back to none.  Also does this for WAN2.  I've tried different combinations, everything in that drop down just changes back to none.

Bug?