Your description of the car successfully booting after several tries is consistent with a weak 12V battery because the DC-DC converter will charge the battery a little bit each time the main contactor closes so the voltage eventually becomes high enough for the car to boot correctly. Did you measure the 12.55 volts at the battery terminals after the car had been turned off for some time (say at least 30 minutes)? How did you measure the current? 0.17 mA is way lower than typical power off residual current. If you still have the Nissan OEM 12V battery, I strongly suggest that you replace it with a high-quality AGM deep cycle battery if you plan to keep the car for several years. The OEM 12V batteries failed after less than 3 years in my 2011 and 2015. There are several threads on the forum which explain why a deep cycle AGM battery is a good choice for reliability.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019