I don’t know but hope that hasn’t happened because I would be much like you and feel badly about it. However, I know of comments I’ve made that were never acknowledged and I don’t think too much about it. I’m not offended but if I see a pattern of ignored comments I generally stop reading that writers content. I figure they won’t miss me! Your good at commenting and paying attention so I’m sure those readers didn’t feel slighted. For each comment you missed you probably answered 50! We all know glitches happen on Medium.