The person who was inconvenienced deserves to know when the fix is actually complete.

Most apologies close the conversation for the person giving them and leave it open for the person receiving. They are still checking, still working around it, still unsure whether to plan on the old problem. A repair is not finished at the moment the work is done. It is finished when the person affected knows they can stop watching for it.

When you fix something that cost somebody time, tell them it is done and what changed. One short message closes the loop. Send it even when you suspect they have already moved on, because they may not have.