based on a report on IRC:
<x> We have a mixture of RHEL and SLES boxes, running on x86_64 and s390x architectures
<x> On SLES 11, the x86_64 is being assigned to the Operating System tagged s390x with architecture
<x> in seems to be fact related, since we manually re-assigned it and when puppet runs it goes back to the s390x operating system

The problem here is, that the lsbdistdescrption fact is used as the display name for the OS. It's e.g. "SUSE Linux Enterprise Server 11 (x86_64)" or "SUSE Linux Enterprise Server 11 (s390x)".