Comment by didibus
The mystery seems pretty much "solved" to me.
We know where that number originated from, it's from this Gallup interview with Gloria Mark.
We also know the Gloria Mark paper corroborates the number:
> When people did resume work on the same day, it took an average length of time of 25 min. 26 sec (sd=54 min. 48 sec.).
From the Gloria Mark paper: https://ics.uci.edu/~gmark/CHI2005.pdf
Now we're only left guessing the discrepancy between her paper saying 25 minutes and 26 seconds and her quoting 23 minutes and 15 seconds when interviewed about it.
My guess is she didn't recall exactly and gave a ballpark as she remembered it.
That seems basically right. I wouldn't have called the Gallup interview the source but I think you're probably right about the paper and the explanation of the difference between what she said and the paper.