I also have a 2017 Eagle HT... but different model. I was of the mindset that with a battery disconnect, it actually disconnects the battery - but as you, and I have found out, that is NOT the case - it disconnects MOST things, but not all. I need to spend a few minutes to find out what the parasitic draw is.
2017 Eagle HT 26.5 BHS 5th Wheel
2014 F-350 Lariat 6.7 CC SB SW
B&W Turnover Ball