Crack in stone

I have just noticed a crack in the stone whilst weighing up where needs repointing. Would you be concerned? All others are sound seems odd that this one is like this next to jobe stone / front door. Repointed 2 years ago. Could workman have cracked it grinding out? Kind regards.

If the slivers of stone are loose then you could take them out, and then reset them in mortar or simply try and seal the cracks with polyurethane sealant from a cartridge. Its not a big issue.

However, could you stand back and pic that doorway and some of the elevation from ground level up.
I noticed a fillet of sand and cement at the ground/wall abutment - these fillets are often mistakenly installed in hope of preventing damp signs that might have appeared on interior surfaces.
Have you detected a DPC in the wall?

Not unless they managed to also fill it with lime mortar exactly matching the original, before reporting the rest with cement mortar and the wrong colour sand

It cracked because it was repointed in cement and not lime... & can't breathe. rake that cement out and get some nice breathable lime in there. If you continue to repoint in cement expect to see this happening elsewhere.