Client interaction

This is a question for all my fellow agency workers…

Where I work, I do interact with clients quite a bit, but I’m rarely the point man - clients are almost always in contact with the project manager, who then relays info back to me. It works well for me, since interacting with clients is one of my least-favorite things (although I don’t hate it, I’d just rather be working on a project). My question is, for those of you who are in a similar situation as me, where you have a project manager or some other intermediary who does most of the client interface: How familiar is this person with web design/development?

I’d imagine almost all of them are at least basically familiar with the concepts, but I’m curious to see how much they make it a point to know. It can definitely cause some issues if the person doing most of the talking with clients doesn’t have as complete an understanding of the subject - they could promise something impossible, etc. Do you guys ever run into issues like that?