To enable Conversation View:
- Log into Gmail on your computer.
- In the top right-hand corner, click Settings.
- Click Settings from the drop-down menu that appears.
- Scroll down to the "Conversation View" section.
- Select Conversation view on.
- At the bottom of the page, click Save Changes.
Once you've done that, if you switch your phone off then switch it back on again, you should no longer experience issues.