When I try to share a document with an external, the People Picker incorrectly resolves e-mail adresses.
E.g. when I try to share with my hotmail account firstname.lastname@example.org, I have not way to choose this e-mail. it always resolved to my tenant test account email@example.com.
The interesting fact is, that both accounts only have the dispay name in common.
Even if i use a semicolon, behind the e-mail address, it resolves immediately to the wrong address and i have not way to see this in the people picker. When it is resolved, i can only see the display name.