There a setting in prefferences. Some thing like midi offset. Not sure abt the name (currently away from computer). It should be at 0. If not all midi data will be offset by the value entered there. Hope someone else guides u with exact details.

set up to accept Windows update ?
Sometimes they reset driver values to their default positions.

I appreciate the feedback, but this is not a driver issue.  The problem is localized to Sonar.  I have Studio One installed on the same computer and it uses the same audio interface through the same driver.   The offset occurs in Sonar and not in Studio One (I posted two screen shots above).
 

chuckebaby
set up to accept Windows update ?
Sometimes they reset driver values to their default positions.

No.  I posted above that I have not installed updates.  I have updates turned off.  Also, I followed the advice above and re-applied my drivers.  It had no effect.

In Preferences> Sync and Caching check if Timing Offset and Manual offset values are set at zero.

sonarman1
In Preferences> Sync and Caching check if Timing Offset and Manual offset values are set at zero.

I don't have Preferences>Sync and Caching. I have Preferences>Audio>Sync and Caching. I also don't have 'Timing Offset.' I have 'Record Latency Adjustment (samples)' that includes Manual Offset, which is currently set to 0, and a check box labeled 'Use ASIO reported latency' which is currently unchecked. I tried checking the ASIO latency box, but it had no effect. My recordings are still offset early.

"MIDI timing offset" is shifted to the right under "Full Chase Lock" which is under "Synchronization" on the "Sync and Caching" page. Maybe you are running a different version of the software?

Read his post # 5 He's up to date. I've pondered this issue and can't think of anything you haven't already tried. But somewhere a setting must have changed if all was working beforehand. 
I don't have an audio interface for this computer so that will make a bit of a difference in settings but here is what my settings look like. You really should never have to change the timing offset for audio in ASIO mode. And this is a midi issue anyway. 

Have any of your audio tracks got a plugin with look-ahead functionality, or maybe just one with a hell of a lot of latency?
 
It might be trying freezing your audio tracks before recording MIDI, so you're not recording along with something that is actually delayed.
 
[EDIT] - I once had this when I had the Lursenn Mastering Console still enabled on the master mix on my old machine (which was SLOW).

msmcleod
Have any of your audio tracks got a plugin with look-ahead functionality, or maybe just one with a hell of a lot of latency?
 

I think you are on to something here.   I by-passed all FX using the button in the mix module and the problem went away.   I never record through plugins, so I didn't think it was FX.   As I understand your post, some plugin on another track can affect the timing offset of a new track I am recording?  
 
Now to narrow down the culprit.  Are there any plugins that are obvious choices?