First of all there is a recall on the Versa Pro with revision 2A software. This problem is well explained here
http://www.scubaboard.com/showthread.php?t=140495. This is not a "calendar" flaw that you mention in your post. (to be honest a "calander" flaw wouldn't be dangerous, having a fast clock u/w and surface mode in gauge mode is...)
The 2 units that are discussed in the recall notice were the two units that owners were using in gauge mode and saw the problem, more than two units are involved however because they all have the problem if the have software revision 2A, thus the recall.
I HIGHLY ADVISE if your unit is a version 2A software revision you allow us to exchange the unit, it is free.
If it is not a unit affected by the recall, I STILL HIGHY ADVISE you discontinue use and return to us for service and the unit is NOT behaving as designed. I do NOT recommend you attempt to "fix" the unit yourself.
Please don't hesitate to PM me if I can help.
Best,
Chris