Hi curious to why POB shows my Vortex gain 300k dps from this support in Cold snap.

I find this rly strange. I usely able to find out why stuff like this happens. Or whats wrong. but this is puzzling to me.

My Vortex gain 300k DPS IF my cold snap change support to Summon Phantasm.
Why would POB think that i gain dps from that gem at all? Its clearly not right...right?

If anyone able to enlighten me understand why this is. I would be rly happy:) Its buggs me abit :P