I think I may have noticed this too. I just chalked it up to something else, but in the last week or so, I have had problems with one-audio half-way into the conversation or sudden pauses. Sometimes I think it's the other person's phone or that they just stopped talking for a bit.
Now that a couple of you have mentioned it, I'll try to keep an eye out (or an ear out) in case this happens again. Hopefully, it's nothing major.