In addition to what others have said, it can also indicate different issues on different printers. Is it a core-xy or bedslinger?
If it’s not just an issue with a dished bed, there could be twist along your x-axis which are moving the nozzle (or probe) slightly further from the bed in the middle. Could be wire/bowden routing putting a slight strain on the toolhead.
Do the mesh results look roughly the same when cold versus, say, a 30 minute heat soak?
In addition to what others have said, it can also indicate different issues on different printers. Is it a core-xy or bedslinger?
If it’s not just an issue with a dished bed, there could be twist along your x-axis which are moving the nozzle (or probe) slightly further from the bed in the middle. Could be wire/bowden routing putting a slight strain on the toolhead.
Do the mesh results look roughly the same when cold versus, say, a 30 minute heat soak?