This bug was fixed in Patch 1.52.100.
I constantly hear this buzzing/humming noise that doesn’t stop. On trying to find the source it seems to come from the talking toilet but even if I delete that, the noise stays.
The noise is the noise that the toilet Potty Mouth 2.0 makes when you use the massage option. If a child uses the option, the noise stays in your game permanently.
Only rebooting the Sims 4 gets rid of the noise
How to prevent
It’s hard to prevent the bug with this toilet since kids also use this option autonomously. The Low-end version of the talking toilet, Talking John, doesn’t have this issue and can be used as an alternative until the kids are grown.