lightroom previewing old version of psd or tiff in the develop module

I have an issue.

Whenever I edit a a PSD or TIFF in photoshop and switch back to lightoom, edits show up... in the library module, when file is visualized, but as I switch to the develop module, Lightroom serves me the previous unedited version (a preview of the file at the time it was imported). This happens with both smart previews enabled or not. Sometimes 'read metadata from file' or zooming force loading the picture and that solves it for a while. 

Any suggestion?