The cause of dilly beans floating in the jar is air in the dilly beans.
The way I've prevented my dilly beans from floating in the jar is to cut slits in the dilly beans before putting them in the jar.
The slits keep the air out of the dilly beans so that they do not float in the jar and also the slits work well to help the dilly beans soak up the brine.
Slitting the dilly beans makes the dilly beans get done faster and taste better as well.
I've had the same issue with pickles as well and I just cut the pickles by cutting a slit down the middle of the pickles as well.
Floating dilly beans or floating pickles does not mean they are bad but it just means there's air in the pickles or dilly beans.