Move selection Line down jumps by 2 lines instead of 1

Hello!

This is first string!
This is second string!

12345678901234567890
This is third string!

If we select This is first string! and move it line down then it correctly jumps down by 1 line but if we select 12345678901234567890 and try to move it line down then it incorrectly jumps by 2 lines instead of 1.

PS - Last line is blank line like line no. 3