PBR Weirdness - bug or layer 8 problem?

Yes. Yes it does. Don't think I haven't been criticizing GL.iNet for the what they're trying to pass off as PBR.

I'm in a similar postion as I build out conf for my Slate AX running v4.8.0-beta9... but I'm going to flash back over to OWRT-SNAPSHOT when done as I'm not travelling ATM. There's no reason you can't flash back to GL firmware the next time they release a 'stable'. Just pull your confs thru a backup in LuCI & keep the 'pure' tarballs segregated from 'GL.iNet's'.

I use OWRT 'sysupgrade' images to get off GL thru the GL GUI -> Upgrade then Uboot's WebGUI to flash back whatever's the latest stable for a shakedown. It takes all of ~3 min to flip... including restoring the tarball.