I would give them three options to consider and find out which is the case.
1 the headset grease is old, rock hard or gone. Have them clean, regrease and see if they can adjust with no indexing.
2 headset has become adjusted to tight and needs to be loosened a bit.
3 grease is fine, adjustment is good but it is just worn out. Replace the caged bearings with loose balls and readjust, see if it gets better. Or, total replacement is what is needed for the unit.

Nice bike! I would lose the kickstand though...