Pressing the delete key in evolution moves the cursor back one space and then deletes the character behind it.

ie if you type in 

abcdef and leave your cursor to the right of the the f character and you press delete 3 times you end up with the string bdf

The delete key also deletes the character one to the right of the cursor.

ie if you type the string abcdef and place your cursor to the right of the string you end up with the string ace

This has only happened after updating to 8.9

I updated another computer with a different user profile and now they are experiencing the same problem.

3.28.5 (3.28.5-22.el8)