Most likely cause is that the schematics are just the same, with the same coordinates, but that your grid settings are different on those two computers.
Always putting schematic symbols on a 50mill grid is the easiest way to prevent trouble with the grid from ever occuring. You can set the grid with Schematic Editor / View / Grid Properties …
KiCad V6 also has a built-in function to fix grid alignment issues.
Just make a selection (can be the whole schematic) then press the right mouse button and select Align elements to Grid from the popup menu.
Ahh that’s it, the windows was set to .050 and the Mac was set to .025 which explains why some points seemed okay. I wonder if I used a short cut to change it by mistake.
A soft way to fix this problem might be just to have a pop up saying that the grid is XYZ, but 50 or 100 mil grids are recommended for drawing schematics.
@BobZ A popup complaining about grid sizes would be awfully bad. And luckily for me most KiCad developers have an equally strong dislike for nag screens.
Personally I’m quite happy with the Align elements to Grid from the popup menu in a selection.
I do see room for improvement, but that would be in the form of snapping to attachment points that are off-grid.
The number of times schematic connection errors caused by forgotten grid changes, have been reported on this forum over the years is amazing
I like @BobZ suggestion, a reminder at startup that the grid was non standard would reduce this a lot.
I have no idea what that is, but I think that the whole sentiment may only make sense if the user knows about using the CTRL key to suspend grid snap. I found out about it only 2-3 weeks ago and it seems that some others on this forum learned about it from my comments.