Linkedin inviting people into my network without my permission?

Linkedin has been acting very oddly recently. I noticed that people who I didn't really know were accepting invites to connect. I hadn't originated those invites. The people weren't entirely random and may have been copied in on emails that had been sent to me, maybe even emails that I had replied to, but were not directly known by me. At one level this doesn't matter, but if people who I don't really know thought that I was spamming them through Linkedin, or even that I was desperately trying to increase my network, this could potentially reflect badly on me.

When I mentioned this a while ago on Facebook and Linkedin a lot of people responded that thy too had experienced this problem. Tonight a local friend called to say that she thought that by connecting with her son, she is not a big Linkedin user, this had triggered invites going out to dozens of people without her knowledge.

I have disconnected all apps with access to Linkedin and found out that those affected have different email suppliers so goodness knows what is going on. Whatever is doing this must have access to our email accounts as the people who are being contacted are not in our personal address books nor even our Linkedin networks.

If anyone knows what is behind this, or can get attention from someone worth talking to at Linkedin, I'd be grateful if you could get in touch.