HTC One - WiFi issues after lollipop update

Hi,

Sorry if this has been asked before, I couldn't really find anything.

I updated my HTC one M7 to lollipop some time ago and have had a really strange issue ever since. I have UPC at home (don't know if it matters) and ever since the update, it keeps trying to connect to the wrong wireless network, not my own. I've never connected to the other network before and don't know the key, so it fails. I keep going into saved networks and remove the wrong one, but it keeps reappearing there. I keep losing my connection to the correct network all of a sudden when it tries to connect to the wrong one again.

The weird thing is, my boyfriend has the same phone, and he has the exact same issue, also since the update. His parents also have UPC and we have their network saved, but when we are at their house we have the same problem - our phones keep trying to connect to another network.

It's so frustrating, and such a strange problem! Does anyone else have the same problem? Any ideas? I don't want to roll back, too much hassle.