In "Arthur the Wrecker", the keyboard and mouse up to crashing to the floor due to Arthur and Buster fighting over getting the treasure chest in the game "Deep Dark Sea" do not have cords plugging into the sockets at the back of the computer, and instead have a cord connecting between each other. In the 1990s when this episode aired, computers always used wired input devices connecting to the actual computer via PS/2 ports when these episodes were being produced at the time.
"Arthur and the True Francine" is intended to be a backstory for Muffy moving to Elwood City and being introduced at Lakewood Elementary School as a new student while in Arthur's second grade. Arthur already has glasses before this event; however in "Arthur's Eyes", Muffy is already at Lakewood Elementary School before he gets glasses.