Suggest Treatment For Intermittent Loss Of Hearing And Sounds Of Mumbling

I seem to have normal hearing, and yet when people talk I miss certain words or syllables, or think one sound/word is another, or sometimes feel like they re mumbling, even though almost all of the online hearing tests that I ve taken tell me that I have normal hearing. Is this normal? Or is there something neurologically wrong with me. (This happens mostly when someone is talking to a crowd, like in a place of worship, or if I am trying to listen to others conversations. One-on-one, i tend to understand 100% of what s said).