RAM preview is skipping the first second of playback, in other words, playing back the preview 1 second after the beginning of the work area.
In the Preview Panel the box for From Current Time is unchecked.
It doesn't matter where the CTI is in the timeline or where my work area is, the RAM preview starts 1 second after the beginning of the work area. However, after the preview plays through the first time it then starts where its supposed to (beginning of the work area). It just started today and it's driving me crazy. I'm on a Macbook Pro mid2012, 2.6 GHz Intel Core i7, Yosemite, AE CC 2012 and AE CC2014 (both versions have this problem).
This bug was introduced by Mac OSX v10.10 (Yosemite). We have worked around this bug in the version of After Effects currently in development, which is targeted for release this spring.