It happens sometimes. More recently (since the upgrade to Beyond) I've had it several times where I try to open a chat and I just get the spinny circle thing on the screen and the chat never starts - meanwhile the SR has been generated on the back end, so when I try again, and again, I end up with a load of SR's generated and the agents quite rightly email back with "there's no information in the SR".
As for Sales chat, IMO that is the biggest waste of time ever. I've tried them on many occasions over the years to get answers to sales related questions and the only answer I ever get back is "go speak to your local SE". Useless, haha