my motorcraft 95 rc, reserve capacity rating
95/2.4 = ~40 amp hours
therefore 0.027amp draw is 40/0.027= 1481 hours at that current draw or 61 days
I think your measured parasitic draw is too low to be a problem, battery or charging system is where i would be looking
if you have a DC clamp meter you could compare alt current production and compare it to your system draw, and see if you are at a deficit
I have a 130amp alt, and it can only put a max of, from memory, 65-70amps at idle when i measured
89 GT gr-40, KB2200(10psi), tweecer R/T,LC-1, 22gal cell, w/tailpipes.