Thank you for your post.
Like "Benjamin Fehr", I am also unable to replicate the issue.
Delving into this further, I did find a way to change the alignment/padding of placeholder text from the Normal style if I used large font size for the placeholder text. Is this a possibility? If not, let me know what Theme you are using, font, style, etc., and I will try to replicate the issue here.
I discovered what was going on: For some reason, positioning wasn't taking effect. Based on the positioning that was set, there should have been no issues. But the positioning was being ignored. Once I set the positioning to something else, and then set it back, everything was fine.
The problem was hard to detect because it involved a disabled field with no borders (what I call an info field). Positioning was causing the field to pull to the left 3 pixels, which, coincidentally, was the setting for left padding. A 3-pixel pull to the left and a 3-pixel left padding led me to believe the problem was related to padding on the placeholder.
It was not. So, I am withdrawing the bug report.