Don't leave communication out of something that needs it ! If you don't you are tricking and actually scamming the person! Especially on a custom thing! Never had that happen till it felt like someone (they did not mean for it to be like this but as I thought on it the feeling like it was meant did) made it feel like they wanted me to not have a say (when from get go I said these colors but other than that you can choose) and to just say thank you for something not asked for or got the ablity to say looks all good or can we change this. I get the something special and put heart/soul into it but you can do that with showing them it before you make it live everywhere like you the commissioner said everything was fine. Cause they be surprised when what they gave you was completely ignored and they might want changes or it could be all good. But it's their piece of art your working on NOT YOURS(artist)! So they need to approve it especially on a custom thing, even if given freedom to chose all traits/accessories but not color pallet. Also If you(artist) ask the person for what they want somewhere(no wip picture just asking) and then go and not use that without telling them, you didn't use what they gave you that's tricking the person getting it thinking they had a choice, when in reality you didn't really care nor wanted that given to you. Now all you as the artist had to do was update the person getting it at all(even in last stage) and could be all fine.
Sorry if people might be fine at first you bluntly ignored them and later think that as they feel what you gave them wasn't theirs, as they seemed to not have a say in it at all to even just approve it. Ignoring your person getting what your making for THEM NOT YOU can end badly especially if the person that got it feels like they were ripped off and scammed by you for ignoring them even for the littlest thing or the whole thing.
Now if it's like a ych thing that's completely different as that's you the commissioner asking for the artist to draw a premade thing in their style