My quick opinion would be a questionable installation (connections/settings) made by the Kit Installers. Have your fuel combustion percent examined on cng to find out the extra load being faced by your car's engine. The same incorrect settings are even messing with your pet supply settings causing the engine to behave differently.
My suggestion, don't let it hang loose and have something done about it.
PS: are u sure its only been like that in these winters...