I had a similar experience with TJ's unbleached AP flour. I don't know what...
...the protein content is compared to Gold Medal (my usual), but last night's House Bread was some of the best in recent memory. Rose very well; crust was perfect and the inside was very tender. So good!
I tend to get the same results with Gold Medal Better For Bread flour and King Arthur's unbleached AP flour -both higher in protein than Gold Medal unbleached AP.
Maybe TJ's uses a higher protein flour for their private label program.
Michael