Marking topics as read unmarks in other branches

Steps:

1. Create 2 branches and create topics there (or have them created by someone else). Let's call them branch1 and branch2.
2. Go to branch1 and mark all topics as read
3. Go to branch2 and mark all topics as read
4. Return back to branch1

AR: All the topics became unread in branch1
ER: The state of other branches doesn't change in regards of read/unread topics.