Many makers prefer to have happy customers who own a nice looking uke, than the reverse. Unhappy customers with a bad looking uke can cost a making business a lot of time and money and new customers. So as long as you are polite and patient (makers are often very busy) you are actually doing them a favour by asking them about issues with the finish or other aspects of a ukulele which they made.
You are doing them much less of a favour by posting photographs and discussing "issues" on social media where their competitors and negative audience can take the opportunity to make disparaging remarks which lead to loss of potential orders and a damaged reputation.
So if you want to look after the maker of your custom uke, within reason, take opportunities to set up a dialogue. Ask them some questions if you need advice on the ukulele that they made. If you have a major problem that needs a repair, give them the opportunity to quote or comment before asking anyone else. If you have a minor issue, ask for advice. And be patient while you wait for reply.
If you like the service, send them a post or testimony to post on their own site so they can have control of how it is used for promotion, rather than blasting it all over social media where you have no control of how it is used or abused.
