Different X offset coordinate of text is used when in titler window and when rendered. Y offset seems to be OK.
How to reproduce:
Have a simple image clip (PNG) with color box
Create a text clip.
Put text precisely into upper left corner (for example).
See my screenshot:
Full kdenlive rebuild (kdenlive_builder script) from SVN sources updated 16.6.2007 (most recent ffmpeg+mlt+kdenlive at that time)