Mono Group Tracks

I have 3 mono tracks that i’m routing through a group track and the onot stereo output.
The problem is sometimes the group track pans the mono tracks slightly off center.
What i’ve done is delete the group track and then add another group track which now seems to have the mono in the middle.
Is there some control in the group tracks that do this to mono tracks ?

Yes, the panner.

The panners are all central.

Then the signal is center also, unless you have some send routing, that sends an additional portion of the signal to only one side of the main out, or you have a soundcard mixer setting, that is setup incorrect. Plenty of possibilities, hard to tell, without seeing.

I deleted all the plugins and fx and it was still the same.
As i said i deleted the track and repeated, now, it’s OK.
Just a reference for future users really to make sure they use their ears and not trust the GUI.