SharePoint workflow task locked (SPBuiltInFieldId.WorkflowVersion is 512 and not 1)

Hi,

I have a SharePoint 2010 workflow on a list which normally runs fine.

In a few incidences the tasks get locked and then workflow cannot proceed (unless we reset it which we do not want).

I noticed that the locked tasks have SPBuiltInFieldId.WorkflowVersion = 512 (as opposed to 1 in other tasks).

Also if I set it back to 1 (using PowerShell or C#) the task gets unlocked and workflow proceeds all fine.

I need to find a solution so these tasks do not get locked at all.

Any help is appreciated!

Thanks so much.