[ARCHIVED] Cannot edit pre-existing sims (Family relationships)

Product: The Sims 4
Platform:Xbox Series X
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 1.70.3.2310
What expansions, game packs, and stuff packs do you have installed? All
Steps: How can we find the bug ourselves? Take a preexisting adult sim and young adult sim, add them to the same household in live mode, then attempt to edit relationship
What happens when the bug occurs? Unable to set preexisting adult sim as parent of young adult sim in CAS when added to the same household. I’m only given the options of household member, spouse, or sibling. I also tried using the cheat “relationship.add_bit {yoursimID} {targetsimID} {relationshipBit}” But it was no use.
What do you expect to see? To be able to set preexisting adult sim as parent of young adult sim in CAS through live mode
Have you installed any customization with the game, e.g. Custom Content or Mods? On console - never used.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

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• Image 1 is the preexisting young adult sim
• Image 2 shows the 2 preexisting adult sims that I am attempting to set as the parents of the young adult sim
• Image 3 Shows the only options available for editing their relationships in CAS