Adding screenshots for the 3 important steps for folder portal menu "Allow navigation". Hoping to save someone else a few hours of frustration. I purged and reinstalled 3 times (totally unnecessary) before I finally realized I missed a step. I was confused & treated these 2 settings as one, but they are actually 2 separate settings within the folder options: "Open each folder in the same window" & "Launch folder windows in a separate process". All 3 settings in screenshots below need to be verified.
1 from hamburger menu on folder portal title — select/check "Allow navigation"
2 under folder options "General" tab — select/check "Open each folder in the same window" & click Apply
3 under folder options "View" tab — unselect/uncheck "Launch folder windows in a separate process" & click Apply