Dashboard sidebar breaking in Chrome – possible bug in 4.3?

After updating a site, I noticed that the sidebar’s layout on the left of the dashboard was broken.

https://pasteboard.co/m4r8htS.png

– Deactivated all plugins and reverted to the Twenty Fifteen theme, but it didn’t solve the problem.
– Switched to Safari which fixed it.
– Deactivated all Chrome extensions and updated to the latest version.
– One of the other guys in our office checked on his Macbook – exactly the same for him.
– Did a fresh install of WP 4.3 to check it wasn’t something I had done. On my fresh installation, it was broken in Chrome still.

Any ideas? Perhaps this has already been reported?

Thanks.

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