Possibly not a bug, but I figure I should mention it anyways since it could be considered a minor exploit. Quite possibly the highest value use since a research kit can get particularly heavy and is essentially a container, and to the best of my knowledge doesn't have an actual cap on its weight.
Magus Tollo Umbra (in case I got the wrong spell name)
Feather Works on Research Kit
Re: Feather Works on Research Kit
Research kit weight is recalculated every time you open or use it. Not an issue.