If you need to work with Calibri then I assume all others will experience the same problem, so then I would not bother about it if I were you.

A solution I found;
One other thing that might have an effect is to go to Office button > Word Options > Advanced > Display and check the box for "Optimize character positioning for layout rather than readability". Then again, it might not do anything noticeable.

But I assume this must be set on word itself, so if you send the file to someone else he/she might see the spacing different.

@JimP what purpose would sending a file have?
just open yours and try out the examples, you should get the same