A little drawback on my researches...
One of my first assumptions is not verifiable...
I can't check if the previous versions of UPlay had the OSI filese installed because i can't reproduce the game launch (those files were probably downloaded as it currently happen at the first launch of a new installment of SH5), unfortunately there is no way to stop the UPlay browser from being updated automatically thus stopping me from doing any trial with older versions of the browser (i can only do a simple check of a fresh installation of an older browser without connecting to the web)...
This issue leave now an hole on my collected data, probably this OSI application was updated to a newer version ? who knows...
A Ubisoft answer on the issue become more important now... i'm not happy about it...
On the other hand i found a good decompiler which allowed me to see the .exe file of the OSI application... digging into it now !
i don't know the C++ Language well but i recognize some part of the program... let's see what i can find !