Young Sheldon finally acknowledged The Big Bang Theory's original depiction of Sheldon's dad, George Sr. Long before CBS greenlit the spinoff prequel, Sheldon's family was already established in the franchise thanks to him constantly telling stories about his childhood in Galveston, Texas. Eventually, all of them made an appearance in The Big Bang Theory as they visited him in Pasadena throughout the years, except for his dad, who died long before he moved to California.
Despite this, George Sr. has the most inconsistent portrayal between the shows. In The Big Bang Theory, Sheldon described him as a bad father; their relationship turned for the worse when Sheldon accidentally caught his father having sexual relations with another woman one day when he came home from college. So it's understandably confusing when Young Sheldon's version of the character is a devoted father and husband who proved several times in the show that he's willing to sacrifice his personal wants for his family. Granted that he has his bad days, overall, he's a good dad, even helping Sheldon in convincing Mary to let him go to college early.
Throughout its run, Young Sheldon has stuck with this version of George Sr., but it seems like this is finally starting to change. In this week's episode, "Cowboy Aerobics and 473 Grease-Free Bolts" Sheldon got a lab assistant job at East Texas Tech after constantly badgering Dr. Linkletter for one. But after he realized that the work wasn't what he envisioned it to be, Sheldon decided to quit and ranted about it to his dad on their drive home. George Sr. got mad, saying that Sheldon should learn to keep his word, which tracks with the Cooper patriarch's belief in responsibility. The narration, however, is what made the scene very interesting. Adult Sheldon said that his father looked so cranky at this point that he didn't argue with him anymore. Since the narration for Young Sheldon is essentially the titular character recalling his childhood, this was a sign that the prequel is finally reconciling the character of Sheldon's dad with the depiction of George Sr. from The Big Bang Theory.
Throughout the two sitcoms, Sheldon's actions are very rarely affected by other people's moods, especially when he's not straightforwardly called out on some of his most outrageous behavior. In the car argument scene, George Sr.'s sour mood appeared to be about something else entirely which might have to do with his recent revelation that he's not happy, both at work and at home. Adult Sheldon starting to talk about this is an indication of where Young Sheldon is going when it comes to George Sr.'s arc. Considering that Sheldon is already in college in the CBS prequel show, it may very well have been the beginning of his downward spiral leading to him cheating on Mary.
How Young Sheldon handles a darker and sensitive topic is unknown at this point, but they can't move forward without tackling such a big formative experience for the socially-inept genius. In his story, Sheldon revealed that after catching his dad's infidelity, they never really talked about it, meaning it was an emotional blow that he suppressed for years. It's the event that colored so much of his behavior in The Big Bang Theory, like Sheldon always knocking three times. Granted, the producers have previously admitted they're more concerned with storytelling than with preserving continuity, but this arc in Sheldon's life is too important to be glossed over.