ivast, linkoval som comment z fora, ktory to vysvetluje takto:
When it gets cold, this is when already thick Shimano mineral oil gets even thicker and has more difficulties to flow back to levers' reservoirs through so called "sniffing openings", which are really small, compared to much bigger "filling opening", which remains blocked/closed by master cylinder piston, if you don't fully release levers' triggers. This results in calipers' pistons not able to (fully) retract as fast as levers' master cylinders' pistons do, followed by next levers' triggers depression, with calipers' pistons not being at their default position, which creates this bite point wandering.
Zjednodusene to chapem tak, ze husty
olej sa nestiha vracat do rezervoaru v pake dostatocne rychlo.