FATAL ERROR while running session with XML GENERATOR and pass-through ports

While running a session with XML Generator using few pass-throug ports I got a fatal error. Here are the last two log entries:


Message Code: XMLW_31037
Message: XMLW_31037 Received all the data for all the XML groups of target [xml_.....]. Combining XML groups into final DOM tree...

Message: *********** FATAL ERROR : An unexpected condition occured in file [/export/home/build_root/861HotFix_build/powrmart/server/dmapper/widget/xml/writer/midxmlout.cpp] line [273]. Aborting the DTM process. Contact Informatica Global Customer Support. ***********


Recreating XML Generator from a scratch and adding the same set of pass-throug ports did not help. Then I tried a lucky guess and changed my bigint ports to integers:
Before:

After:

Effect:

It worked. I still don't know why, though...