What causes crackly/hissy sound to peoples voices? I get this at random for a day or two, along with ear fullness/pressure

It sounds like I am hearing distortion when talking to people or voices around me, mainly voices sound like through a broken/blown speaker or a poorly tune radio station. Voices sound like they are a bit robotic and crackly/hissy. It is subtle but I notice it is not right. It is annoying and is in my left ear, my left ear never does not pop as well as the right ear in general. And when I am experiencing the issue, it is really hard to pop the left ear. The pressure that comes with it is annoying. It is like I am getting a build up of something. I have a camera otoscope and cannot see any wax.

Any ideas what this could be?

Thanks

What kind of hearing aids do you have?

It’s not the hearing aids.

Sure sounds like you should go see an ENT doctor.
Have you had this problem long?

Maybe a pro will chime in?