Rob O,
Sorry I didn't see you sooner. Are you confident that your therm is accurate. Have you tested it lately?
If so, then it's possible I checked back through some of my older logs and I have had chuck rolls and briskets at 145 or so anfter 4
hours, so it's possible.
If you have trust in your therm, then trust what it says.
What temp is your cooker at?