Private message icon and link aren't fully overlapped

Preconditions
User1 is logged in and has permissions for sending private messages

Steps to reproduce
1. User1 opens topic with User2 post
2. User1 hovers top part of private message icon in User2 miniprofile

Actual result
Tooltip is "jumping", cursor switches from pointer to hand and vice versa

Expected result
Tooltip and cursor as pointer should be shown without blinking

Note
It seems the cause of bug is not full overlapping of img and a tags (take a look on attached screenshot, blue region is block of a tag )

Source report
http://javatalks.ru/posts/236342