EPM: Grandstream basefile for DP715 has VLAN Tag set to 0 (zero) instead of undefined by default

I was having trouble getting a Grandstream DP715 to get into the right VLAN (it was supposed to get VLAN Tag info from the switch via LLDP-MED) and figured that by default, the basefile for the DP715 Grandstream phones (and maybe some other models too?) has option P51 set to 0 (zero). Option P51 defines VLAN Tag.

I believe that option P51 should be undefined by default. I set it manually to undefined in the basefile and DP715 started to go into the right VLAN as expected.