When Amy and Jonah are stocking shelves next to each other and having their awkward conversation, the quantity of boxes on Amy's shelf keep changing between most shots.
When Jonah and Amy are dressing in the Minions costumes, they still have their normal clothes on underneath. When they are fully in the costumes, they suddenly have tall yellow socks and over-sized black shoes, not their work slacks and sneakers they had been wearing. No such socks/shoes were seen with the costumes previously, and it would be impossible for them to have put them on after donning their costumes anyway, as they had to help each other into the costumes (the rest of the staff was rushing to fill shelves) and they had no use of their arms once inside the costumes.
Glenn states that at "hour 2, minute 12" of Pirates of the Caribbean: The Curse of the Black Pearl (2003), one of the pirates is wearing a watch, which Glenn refers to as a goof. This does not actually occur in the Pirates of the Caribbean movie, making Glenn's statement a goof about a goof.
When Jonah and Amy are "driving" to pick up the Minions costumes, the gear selector is in the Park position.
Glenn misunderstood a memo from corporate and didn't have the store prepared to open in time. However, the building itself was still under construction. The construction would have been contracted through the corporate office and they should have known the appropriate day to have the building completed (or, if it couldn't be completed by that time, then they would have made corporate aware of the delay). Even if the staff and product weren't ready to go by the re-opening date, the building should have been.
Glenn is shocked to learn that other people find his voice to sound weird. In Mateo's Last Day (2017), one of the trolling Yelp reviews left by Tim (aka Frenchfryguy81) referred to Glenn as the "Muppet-voiced manager."
The Cloud 9 employees are said to have walked 23 minutes away from the store, yet the store is still visible, probably no more than a block or two in the background. The average person walks between 2.5 and 4 mph, so walking for 23 minutes would put them close to a mile or more away from the store and it would not be so visible, if at all.
Glenn discusses theories about whether Allah or the Christian God is the one true God. "Allah" is just the Arabic word for God. Both Islam and Christianity are Abrahamic religions (as is Judaism) and so both of their monotheistic deities are the same God. Someone as religious as Glenn should know that.
Glenn tells Jonah that the men's bathroom key also works on his house. The men's bathroom does not have a lock.