Amphead phase problem

Mar 11, 2005
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England
I owe a 5150 mk2, a triple XXX a Framus Dragon and a Randall Isocab.

Ive just reamped the same guitar part through each head running with the Isocab. The mic position, pre amp and everything else stayed the same and only the head changed for each take.

When I played the takes back I noticed that the triple xxx take was out of phase with the other 2. Ok this is easily enough fixed but has anyone else had this? Is it normal?