Ribbon Tab automatically resizing

Hi,

When working with dual monitor set up, I like to move some ribbon tabs to the second monitor. The problem is that after working for a while, and unexpectedly, the "Home" tab gets resized. I couldn't replicate the problem, because it happens when you perform some action or feature (like finishing a sketch) but not always.

Here is my starting layout:

Here is how it looks after working for a while:

Has anybody faced this? How can I solve it?

Many thanks.