Welcome to the forum.
No, it doesn't seem right but I don't use RV antifreeze, except in the P-traps. Hopefully someone will be along with better information.
My guess is that it could be the valves on the water heater are not set correctly and the water heater is filling. Take another look at the bypass vales and maybe pull the drain plug and see. That's all I got.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.