Why is the 'modifyrelationship' cheat not working?

Product: The Sims 4
Platform:PC
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? 1.50.67.1020
What expansions, game packs, and stuff packs do you have installed? Get Famous, Seasons, Pets, Get Together, Get to Work, Strangerville, Parenthood, Dine Out, Laundry, Bowling, and Movie Hangout
Steps: How can we find the bug ourselves? Attempt 'modifyrelationship' cheat between two Sims.
What happens when the bug occurs? Nothing; the relationship isn't affected at all
What do you expect to see? Relationship to be modified
Have you installed any customization with the game, e.g. Custom Content or Mods? Never used.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

‌

The 'modifyrelationship' cheat isn't working in Sims 4. I've tried it several times - both with and without the "LTR" in the front. I've also made sure that none of the Sims have 3 names, just two. What else could be the issue? Thank you.