Hi Alexander The Great,

I think I more or less was able to reproduce what you describe:

Please confirm if your TM has the upgrade symbol when viewing it within your project settings: 

The reason why I was able to reproduce the TM track change despite 4 mm had not changed between TM and TU was because I amended my TM settings:

And when doing that I got this warning, which I subsequently ignored, which caused the warning:

So in summary, please check your Language Resource settings, and I should think you would want measurements enabled. 
Please  also ensure you have upgraded your TM.

Hope it helps!