I've had hens sit on the wrong nest for hours, and even had this happen during temps in the 30s. It's fortunate that they are designed to withstand variable conditions and absences, or we would have a lot fewer birds!
I wouldn't worry, but make sure when she gets up for her pott/eating break she goes back to the correct nest. THey can be off for hours, however, and still have a successful hatch.
Thank you! This mom in particular, has 2 babies that are two days old and two more eggs soon to hatch (I hope) and has left her nest in order to train her chicks. She is taking her time with the chicks, which is great she is an amazing mom, I'm just a little nervous about those eggs, shes been off them for about 2hrs.