Going by recipe instructions and timing, it does call for a pretty long secondary, and the temperature you referenced depending on your yeast choice certainly lines up.
Do you have prior similar batches you can compare your results with the asks and recipe requirements of this one?
If you add the primary and secondary max timings that it states, you could be up to 6 weeks in total (1-2 wk primary, 2-4 secondary).
I think this one needs the extra time and I did a total of half that time (low end), which I consider it to have turned out pretty good.