Hi @LukeB, thanks for your patience. I looked at the case, and this is similar to another post: Dropdown issues - General - Forum | Webflow
We do not have support for scroll on that navmenu when opened in dropdown mode. I am sorry about that. We have it on our list of things to update, althought I cannot give an exact ETA for that yet. My best suggestion is to try to layout the content differently on mobile in that menu, perhaps show two icons across instead of one.
Perhaps others who faced this might suggest some design workarounds. For the time being, can experiment with the layout, one that does not need scroll on that navmenu.
I hope that helps, Dave 