Clock Skew introduced in RPI versions 3.6.x

When I run a sys-installed Alpine 3.5.2 on RPI everything is running fine if I replace hwclock with swclock.
However all Alpine 3.6.x versions come up with clock-skew warnings I can't get rid off.
With an upgrade from 3.5.2 to 3.6.x same thing. It looks like something in the openrc version changed
this behaviour. Anyone any idea?