Automatic weight bones fail

Dear Blender community,

I am modelling a hand covered by a glove. By applying automatic weight on the hand bone structure I get strange results. It looks like there is a hidden second mesh but there is only one object

Does anyone have a clue whats going wrong here?

There is a difference between one mesh and one object. There almost certainly are two different surfaces in your hand. Maybe a solidify modifier you applied? Get rid of the generated solidify thing, and if you need it, don’t apply the solidify until you’re happy with your weights, or better yet, don’t apply it ever.