Imaginary Friend Vanishes when making real

My Sim is becoming a teenager, and I suggest making my imaginary friend real, but when they turn to become a real Sim, they simply disappear. They are completely removed from my relationship panel, and after a while, they turn back into a doll. Then the interactions become similar to seeking comfort from an old friend and memories; as if I sent them away forever. I had MCCC and UI Cheats and other mods installed, but I removed them both, and it still happened. Both Sims were best friends with this version of their imaginary friend before they grew up. Does anyone else have this problem?