Thanks for that. I tried it out and it appeared to work but as soon as I had changed the padding on the third tile it started to break again.
I tried defining a percentage width for the text container rather than use padding and I got exactly the same behaviour. Doing the first 2 tiles fixes it but if you fix the rest it breaks again. The fact that zooming out within chrome makes a difference is even more baffling.
Any other suggestions?
I have fixed it by reducing the size of the padding, it works but it's not ideal so a proper fix is still welcome