we decided long ago to not chase "family ties" to a clan that would pressure their daughter as they pressured He Qingge. She ran from them and they were never family for us, and so we wouldn't consider them family just because they used to be mom's family.
this then extended to a low number of retcons for the Royal Road and official release versions centering around plot hooks the thread never chased. If I had to guess, this is where those threadlines are actually going to pick up. My lunatic theory is that this is the Bai we'll be meeting at end of month doing us a "favor" by giving the pretext to persecute and avenge the wrongs committed against our mother, which does a number of other things as well.
1- it's a flex. They've been at the shadowed intrigue behind a brilliant white tyrant game for longer than anyone. This would be a flex.
2- it gives them a measure of who we are and how we'll handle ourselves, or if we turn out to be so unformed in this regard at least puts forward a strong suggestion that the Bai way is an excellent one. Defensive, Observant, and when the time comes Provoking your enemies into making attacks which your brilliant tyrant can fully crush alongside you.
3- it's a reminder. "Weird Cousin Meizhen" may think she can escape Bai style politics at her post in the Emerald Seas, but being noticed by Suzhen means she's noticed by many Bai. Whether or not she likes it, she'll need to keep her Bai skills sharp because at some point she'll be back.
4- it's a sign of Bai-Cai coordination. It's a warning signal to any hostile intrigue nets that the Suzhen-Bai faction and the Lady Cai's forces are both studiously involved with the lady Cai's heir as well as the retainers and Meizhen. A show of cooperation that increases the risk vectors any potential hostile operation will be exposed to, and thus reduces the odds anything is actually tried.
5- it's a challenge to her heir's promising retainer. Shenhua approved of our sincerity, stealth, and willingness to do wetwork on behalf of Renxiang when she saw us. This sort of "attack" so clumsily executed shouldn't be an issue for one such as us, and has the potential to prod much growth. How will we choose to prosecute an intrigue challenge that may be on a more personal level than is typical? By what mechanisms do we enact the investigation and punishment? This will help us develop answers to these questions, if we don't already have ideas for how to answer them.
6- it's a wake up call for her heir, her heir's retainer and that retainer's Bao suitor. They're entering the world of adults now, and this is one of the least damaging ways to obliquely remind them to keep their wits about them. Without having to spend the time to do so personally.
7- it's an opportunity. Meizhen has consistently been considered extremely kind by Bai standards, as well as competent. If her allies at her post are going to be dealing with adult-level intrigue this is a chance to further ingratiate herself with them by sharing some of her talents and knowledge, as well as sharpen/hone those skills of hers before she inevitably returns to Bai politics. The political out maneuvering and subsequent beatdown of Sun Shao's beloved great grand daughter are an excellent start. Time to keep moving forward.
8- it's pretext. But not just for us. The actions of this Liu clan in relation to our family are almost certainly impersonal "Hui-like" abuse of power and corruption normally excused and allowed in the corners of ex-Hui Emerald Seas. Shenhua has always placed emphasis on rooting out such corruptions, and whether or not this is pretext against the Liu clan overall or if the Liu involved in this scandal will simply be made examples of so that the others shape up is unknown. I do think, however, that if Cai agents had done their homework they'd see the kind of corruption involved in mom's story and start shifting things to do something about it. Not as a personal favor, but because that's what Cai rule is all about. Burning out corruption.
so that's my lunatic 5D chess game theory which is probably nonsense hehe. Broken clocks and all that. Totally possible no Bai are involved at all and it's just Cai or Diao agents. Or none of the above and it's actually just that braind-dead of a move from that same vengeful Liu.
Anyway:
given the fact dad was in a troupe whose elders performed for the local viscounts, it's probably true that those same elders had a fit when the Liu scion appealed up the chain to do something about that disrespectful He concubine trying to run off with a member of that foreigner troupe. Whether or not those elders gave dad to Liu jailors, locked him down, or only pressured him strongly to not choose Qingge is up in the air. Even if he had chosen Qingge (which he might not have), I doubt that Liu would have allowed such a thing to occur purely on principle.