might sound as if you have no idea on his recent job, a shoemaker or a preacher. Of course that shouldn't cause any confusions in a real world, but someone like me may find it a good opportunity to crack a joke, "C'mon, did anybody tell you I was fired? Hell no! I'm still working at XYZ Corp!"
because it's both natural and the least ambiguous. But wait... プロジェクトをしている might slightly sound unnatural. Its more casual form
is perfectly OK, but for some reason, プロジェクトをしています is not perfect. Perhaps because, verbs like "する" "やる" are not genuinely polite, so their polite forms don't perfectly make sense. Well, I guess 90% of native Japanese speakers just accept either ways :-)