If you move the caret to the middle of the text, when you type the keyboard copies a section of the text.
If you type
aaaaabbbbcccc|
move the caret inbetween the a and b
aaaaa|bbbbcccc
and type d, you get
aaaaabbbbccccd|bbbbcccc
instead of the expected
aaaaad|bbbbcccc
The problem is noticed on an android with Google keyboard. No problem editing text on PC.