This isn't an issue by any means but it is just so peculiar and happens every day. We adopted two cats, Linus and Lucy (littermates), a few years ago. About 8 months later, we adopted Gracie. Linus was rambunctious and liked to play-fight and Lucy wasn't so into playing. When I read Gracie's profile about "needs a playmate... does better in a household with another active cat", she turned out to be a perfect fit. They all get along really really well and there are never any problems.
Lucy is a little independent but likes to groom the other two. Gracie walks up to her a lot and will head-butt her chest, trying to be groomed. But the weird thing? Whenever Lucy is walking to the food/water bowl, Gracie will come tearing in from wherever and try to beat her there. Like literally walks only 6 inches at an angle in front of her--totally preventing Lucy from getting ahead. (And sometimes stops her for a groom.) By the time they get within a few feet of the bowls, they just go their own separate ways (not even to the same bowl) like nothing happened. If to the same bowl, there is no issue while they eat. Lucy remains totally unfazed the whole time. Any theories? Maybe it's just like a game to her?
Re: Strange cat behavior
It sounds like Gracie is just being an annoying little sister. :-) My kitten does the same with my 8 y/o cat.