At this time, I haven't found any public document from IBM.
I raised a case and this is the conclusion. Hope it helps you.
=====
We have been checking internally and have come to a conclusion.
Unfortunately, not all attachments uploaded to the Case, as you know, worked for TPAE 761.x, that is, the iText Software (Library) is unable to convert all Scanned files, as I had previously mentioned.
That said, we released our new versions of Maximo Application Suite 8.x, and fixed this problem by using the GroupDocs Converter Software (Library), which when tested in our Lab with its Attachments, all worked as expected.
Our best suggestion at the moment would be to encourage you to Upgrade to the Maximo Application Suite 8.x, where you will no longer face these types of problems. But, we are aware of the Companies' Bureaucracies, in choosing to continue with the Maximo TPAE 761.X. Therefore, we recommend that you upgrade to the most recent version of TPAE, which is 7613, as version 7612 will become Obsolete from January onwards, where corrections will no longer be released.
With this, we could make a request to the Dev team, so that they evaluate the possibility of updating this iText Library to the GroupDocs Converter, but we cannot guarantee that this will be effective.
==============================
------------------------------
Carlos Galindo
NC
------------------------------