I've seen the same issue a few times recently.
I think it happened today when I updated the app.
I was just using the default window and had multiple tabs open. When the app relaunched my browser looked the same as @onion's screenshot. It was rectified by holding ctrl+tab to cycle through the tabs which got them to load and the titles re-appeared.
Just for peace of mind, I saved my current tab state as bookmarks and interestingly loading multiple via Bookmarks / Open In New Tabs does load the titles without having to switch to the tabs, so if you're not wanting to store state, a similar behaviour would probably suffice.