Creating a dual class PC in a campaign?

[RuneFell]

I'm creating a new campaign, and before even adding any characters or PC's, I went to set up the options I needed. As it's a smaller group, I'm allowing Dual Class PC's to help make it up.

I went to Shared Options, and Dual Class PC's is checked under the Optional Rules Tab. It is saved, and when I leave and come back, it's still checked.

However, whenever we try to add PC's, it won't add the Dual Class PC option. It's unchecked and greyed out in the PC's options. We even tried creating them with dual classes outside of the campaign and introducing them into it, but it just takes off the second class. To be clear, the option is still checked in the campaign options, I just can't find a way to activate it in the PC's character pages.

I feel like I'm being a bother by constantly creating tickets, so I thought I'd ask here if I'm missing something obvious before creating another bug report.