Any time I read an e-mail in Pantheon-mail and click (a link or something) I get all the mail scroll (up or down) to the beginning of the mail body.
For example, if I open a new e-mail (upper half of the image) and JUST CLICK the viewer will jump from the very top to the beginning of the mail body (down half of the image).
This is true for both right, middle and left click. This is true for only the first click per message.
EDIT: added a bug-report: https://bugs.launchpad.net/elementaryos/+bug/1671477