This is expected behavior. Once the image is rasterized (imported), changes can't be made. The rasterization 'fixes' the image.
No, I'm making a new title by importing the same AI file is all rather than expecting it to do an update.
Besides, that still doesn't explain why the icon in Ttilers tool panel shows the updated image but the Titler work window doesn't, does it?
I am also having odd title tool behavior (bug) in CS 6 (PrP 6.0.1, Mac OS 10.7.4).
I right-click within a title and execute: Logo/insert logo...
I insert a PSD logo -- this seems to work.
I do more work to the PSD file and re-save.
No update in PrP. OK, fine, it's just using a copy of my PSD...
BUT when I delete the old logo in the title tool, and try to insert the updated PSD, it still uses the old PSD, even though that file no longer exists.
I've opened and closed the title tool, but get the same fantom insert of a non-existant file (probably taken from a cache or preview file)
My work-around is to save a version of the PSD file, and import it. This works so far.