OpenVPN Clients reach only some remote MPLS addresses, LAN client reach them all

[nuclearstrength]

I have an MPLS connection, it's through a router on the subnet of the LAN interface.
There's a static route on the pfsense box for the remote mpls lan via the mpls router IP.
I also have an OpenVPN server setup on the pfsense box, the remote mpls lan has been set in the local lan section of the openvpn config.

Hosts on the LAN interface can ping 22 hosts on the remote MPLS net, all of them.
hosts connected via OpenVPN can only reach 11 hosts on the MPLS lan.

I'm buffled by this behaviour, any suggestion or direction is appreciated.
the pfsense is virtualized, in order to get MPLS to work I had to select the option Disable Hardware checksum offloading, Disable hardware TCP segmentation offload and Disable hardware large receive offload.

the option Static route filtering doesn't have any effect on this behaviour, just to be safe I added floating rules to open all traffic, ICMP and TCP/UDP between the OpenVPN subnet and the remote MPLS subnet address, all to no avail.