We are having a bit of a discussion about the art of the possible with the defect on the door in the image what repair should be made.

1.       Ignored

2.       Monitored

3.       Re-lipped

4.       Replaced

Any advice would be greatly appreciated

Judging this in isolation. This defect appears to have been caused by the fixing screw being inserted without sufficient piloting.  Fortunately, the split in the hardwood lipping appears to be slight.

If the this is a new door installation, then the defect should not be accepted. The door should be repaired by re-lipping in accordance with its certification (if its a fire door).

If the door is existing and say been there since the building was built, then ask yourself how long has it been like this?  Let's say the answer is two years. Has the defect got worse in those two years?  YES or NO    From the picture, it looks like the answer could be no, so you could justify filling with acrylic wood filler and monitoring the defect.