The "improved Ventilation" label also appears vertically (with additional 'text') when you hover the mouse just to the right of the actual label. I was not able to get this bug to repeat with any other label.
Steps to Reproduce
Call up the tech tree and hover the mouse just to the right of the "Improved Ventilation" label.
Status: Known Issue
We are aware of this issue and have it logged internally but either we do not have a fix ready yet or we are not planning on addressing the issue in the immediate future.