Not really a bug, but thought I would report it anyway.
My CPAP time is 20 minutes behind my current timezone (Sydney Australia) so in preferences I have set CPAP clock drift to 20 minutes (Preferences.PDF).
When I look at the daily Screen (Daily.PDF) the current value at the cursor position shown above the graph on the left (A) appears to be the value from 20 minutes before where the cursor is positioned (B)
SleepyHead v1.0.0-beta-2
Build Date: Apr 22 2016 14:39:45
Revision: cb213cc (master branch)
Graphics Engine: OpenGL
Philips Respironics
DreamStation
CPAP Pro (400X150)