Kim, Francesca, and the audience are able to hear Jimmy's guitar from reception, even though his door is closed. But when they leased the space, Jimmy demonstrated that the offices were soundproof and made a big deal out of it.
Near the end when Jimmy is trying to get himself and another person out of trash duty, the long shots show him in the sun, yet the close-ups show him in the shade.
Inside the grocery store Chuck passes a display case selling Shock Top beer. The show takes place in 2003 and Shock top wasn't founded until 2006.
Chuck goes grocery shopping at Triangle Grocery whose only location as of 2020 is in Cedar Crest, NM. Chuck lives in Albuquerque. He would have had to walk all the way up and over the Sandia Mountains or followed I-40 to the south to get there yet casually carries the groceries back his house stating it was "just a little stroll."
Nacho tells Daniel (Pryce) that he needs empty capsules from the manufacturer so they'll still be sealed in order to avoid suspicion from Hector, but then opens them himself to fill with powdered aspirin before swapping for Hector's prescription.