I used to have a car stereo business and the first motorhome I installed a radio in went perfect until they went to leave a 4 am... at 4:10 i got a call. When they turned on the headlights it blew out the radio and dash lights. Seams what was a ground was only a ground when the lights were off. When the lights came on the ground was variable to dim the lights to the factory radio. That might be what they are calling a floating ground. Some might call an isolated ground incorrectly a floating ground. If you are doing your own install then just double check the factory harness with and without the lights on and off. Best of luck.
2013 Tiffin Alegro 32CA
1996 Itasca Suncruiser 29RQ, 7.4, P32