I think what's happening is that the new auto-NSFW patch is checking the box visually, but isn't letting Lemmy know about the box actually being checked.
Here is the code that seems to be behind it. It's setting .checked true, but there's a change event Lemmy registers on the checkbox, which I'm not entirely sure if it gets triggered or not.
This seems like a really roundabout way of going with this, but I'm not sure how hard it would be to do the 'proper' way. It's 4 AM and I really should be sleeping instead of lurking here.
I guess I’ll use the uncheck and recheck method until I hear its fixed
with how the patch works, sending untagged and tagging afterwards would be more reliable, as it only runs on the 'create post' page. but then i'm not sure how well this would affect the federation (it's certainly better than keeping it untagged)