I'm probably missing something very obvious but it seems like /users/{ids}/answers forgets to include the tags badge in the resulting answer object:

tags (2.1) an array of strings

Nowhere does this mention that it may be absent. So, I gather that it must be included with every query that I make to it. And yes, I'm using the appropriate filter.

Interesting behavior: Sometimes, I do see the item, but not always.

Here's a demo of the bug.

I read somewhere that fields with null values are excluded, but I always understood that to mean fields marked with may be absent only.

So, is this a bug?

Editor's note: This appears to be similar, but not the same as the bug: The answer object returns an empty array for tags. The workaround there does not work in this bug's case.