I don't think it's been spelled out, but it's implied to do with a role that Chen Mo had written and promised to her sister previously:
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch35#2 (bottom of page)
which she did not in fact end up playing. Something happened, and afterwards Qingyan was especially bitter toward people 'parachuted in from Chen Mo's agency'
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch38#1
Which might imply that Mo was pressured to select someone else. But a few things make me doubt that's quite what occurred.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch38#6
Has Qingyan dismissing the promise rather than displaying a grievance about things, with Mo merely fuming.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch38#5
Has Qingyan quietly irritated at being referred to only as Mo's sister. Plus that very first link makes me think the web series 'Impressions' that Youji starred in was the role in question, which combine to make me think that Qingyan was offered the role and unexpectedly turned it down cold; possibly because she felt that if her first big break was a chance handed to her by her sister, no one would ever respect her on her own merits.
Alternatively, it could be the original use of that script was intended to be another format originally, but Mo was pressured to make use of someone other than Qingyan for the lead role; and eventually decided to pivot it into a flagship web series instead, knowing that the talent being pushed on her would back out of things due to the perceived lower prestige involved. In this scenario, Qingyan was already not speaking to her by this point, and so she had to cast someone else, and Youji was a prime choice.
Or at least those are my two guesses. Either way, I think those links are all the relevant bits we've been given.
Edit: Forgot one tiny detail:
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch40#14 -Name on the script Youji is handed
last edited at Feb 25, 2026 10:48PM
