Well that's quite interesting.
Although references where up to date, the name was different OnInitializeScreentoPDF.. I removed the dependency completely, and re introduced it, and became ScreenToPDF_OnInitialize .
Now i can't see in the console log the error, but on the server it is still present, and PDF is corrupted.
On server, the error is the following:
UltimatePDF.OnInitializeMissing: ScreenToPDF_OnInitialize action must be invoked during the OnInitialize event of the screen
However, if i may point, my setup is as follows..
Screen > Calling 1 Single Block and onInitialize of the block call UltimatePDF. Could it be the reason of the issue? and if so how can we manipulate this since this block is reusable ?