Forgotten MH Fact #223: 

(OOG) The shot in TTA’s Reminder of Jay checking out the antique shop was inspired by a goof in Entry 53. The reflection that can be seen in the glass in 53 was actually Joseph (Alex) standing in the background; when the entry was uploaded and fans noticed the figure, the series creators decided to run with it. 

Forgotten MH Fact #217: 

(OOG) At some point between Entry 38 and Entry 50, Joseph (Alex) misplaced the blue striped jacket that Alex was wearing in 38. Since Entry 50 takes place immediately before and after the events of that entry, a replacement jacket had to be ordered from online in order to avoid a glaring continuity error, causing a delay in Entry 50′s production.

Forgotten MH Fact #153: 

(OOG) According to the series creators, the infamous “Skully” mask from Entry 26 was originally intended to be a hint towards Jay having an alternate “masked” personality similar to Masky and Hoody. This idea was eventually scrapped; however, this apparently doesn’t necessarily mean that the character in the mask isn’t still out there somewhere. 

Forgotten MH Fact #14: 

Before they check into the hotel in Entry 52, Jay asks Jessica to come up with a combination for his safe. She suggests 1234, but Jay says that would be the first thing he’d try. 

In Entry 28, which chronologically takes place after the events of Entry 52 and Jay losing his memory of the last seven months, 1234 is indeed the first combination he tries on the safe.