Yeah, I did my first two over the weekend and that happened to me too!
I laced both of them up, and only after finishing the second one, did I realise that the spokes around the valve hole weren't perpendicular (that sweet spot was one set of spokes to the side).... ARRRGGHHH!!!! Like you said, not a critical error, but could be a pain in the ass for accessing the tire valve.
So I thought, "Heyyyy, no problem! I'll just move all the spokes one hole over and the valve will be in the right spot!"
Well, that meant completely undoing a spoke and removing it from the nipple, then completely undoing the spoke beside it, and plugging that spoke into the previous spoke's nipple. 32 times for each wheel. What a pain in the ass that was.
And after I went to ALL that work, only then did I realize... the spoke holes in my rims were offset to one side of the rim or the other to work in accordance with the alternating spokes from either side of the hub. So my brilliant place to avoid completely disassembing the wheels and relacing them again (which arguably was probably just as much work as doing it properly) actually dumped me with 2 completely incorrect wheel builds!!! So I took two properly laced wheels, except for the minor technicality of the valve hole in the wrong spot, and ruined the lace jobs. Had to redo both wheels lacing jobs from scratch again.
It ended up taking me a solid 2 hours to lace two wheels. Ack.