ALM is Ent 11.0.0.8178, the server is SaaS.
UFT is 11.52 B0467, ALM Connectivity Version is 11.52.341.0
The source XML is modest, around 32Kb. The point of truncation appears to be random in any case (that is, it doesn't always truncate in the same place).
I've tried replicating this doing manual uploads and the file seems to upload okay, so at the moment I suspect this is more likely to be an issue with the UFT "UploadResource" method. Either that or it's an issue specific to the SaaS provision.
I note that my UFT install has "ALM Storage" version 11.50.0.0 (in case that's relevant).