If you check out the reviews for the DVD set on Amazon most of them mention it, and it was also confirmed by posters on the IASIP sub. I think the timing was unfortunate because it was released in the midst of the big streaming cull, but it's still beyond the pail, IMO, to even do it on a physical release.
Wow, all the reviews on Amazon complain about this as well. What a joke.
Try the Amazon one
Season 14 isn’t on Blu-ray but it is on DVD. Sadly, it’s being price gouged:
It's Always Sunny In Philadelphia Season 14 https://www.amazon.com/dp/B08JLHQHWV/ref=cm_sw_r_cp_api_fab_pG1CFbVVKG00N