I'm having the same issue with my OpenVPN setup, although in my case, if I set all/rp_filter to 0, and then reset it to one, it works [so long as my tun0 device is set to 0].
I'm having the same issue with my OpenVPN setup, although in my case, if I set all/rp_filter to 0, and then reset it to one, it works [so long as my tun0 device is set to 0].