Very slow coolant leak main battery pack 2013

Always suspected I have a very small coolant leak from the main battery. Anyone else had this happen? No Dtc's yet. Seems to happen on odd occasions after charge, I charge at level 2. The marks on the concrete floor is after two months - evaporated coolant one can see the red colouring. The level in the resovoir is very slowly going down from where it was at maximum over 12 months. Hoping this is not serious and can be rectified under the battery warranty. Otherwise all going well over 5 years and 21K Driven mainly on battery and short distances. Like the L as it provides a very nice one pedal drive. Summer A/C is excellent, but winter would still wish to override the A/C but that will never happen as that is how GM operates. Situation normal ?