This is a common problem that a lot of S5 users have been reporting. It has prompted many people to wish they had not installed the update, but unfortunately, there is currently no way to roll those updates back. I've been reading on different Android forums about the problem, and it appears to be linked to the update. While the evidence is just circumstantial, there certainly is a lot of it. If it is due to the update, and not to something else the user did like installing a new app, then we can only cross our fingers and hope a future update corrects some of these problems. The good thing is that the Galaxy series is one of the most popular, and so there is a lot of manufacturer and community support for these devices. Hopefully there will be a fix soon. I've learned that it is a good idea to research any software update in the various Android forums prior to installing it, although I know that is probably asking a lot of some people who aren't as 'savy' as others.