please check the variable “java.io.tmpdir”, which should refer to the local temp directory of your JVM, and the file system, on which it is located , if there is enough space on it.
The value specified is the equivalent of 50MB, so when you try to process several of these large files, this means that the directory can only hold one file of size this you mentioned (32.5MB).
For the 25MB size: there will be only 2 of these fit in this directory, the third one will fail.
From the IS Administrators Guide 9.12 for the maxSize parameter:
Tip: The size of the hard disk drive space for temporarily saving documents
will vary based on the number of documents that you process concurrently
and the size of the documents that you process. For example, if your
typical concurrent document load is 10, you would need a hard disk drive
space that is 10 to 15 times the combined size of the documents being
processed concurrently.
See IS Administrators Guide for further informations on the mentioned settings.