There is a bug in how 'character' units are handled between systems in different operating systems (specifically operating systems with different system DPI settings).
As a workaround, the 'Units' can be changed to something other than 'characters'. 'pixels' are system dependent, and should scale all elements depending on the system DPI settings. 'inches' and 'centimeters' are absolute units, and scaling should not occur. 'normalized' units are generally considered good practice, but this will scale the elements based on the size of their parent, so this can have a cascading effect on GUIs.
Changing the 'Units' negates the advantages of specifying 'characters' as 'Units', so text may not fit exactly the same way inside its containing object. It is recommended to leave extra space around the text to ensure that even if the element shrinks or the text size grows, it will still display as expected.
Another workaround is to simply rebuild the GUI in the system that appears to have the issue. However, considering you work on both interchangeably, it will not be a sustainable solution for you.
Hope it helps you to understand the issue.