This is caused by the enhancement in functional map behavior in WTX 8.4.1. When the output card of a functional map is an item, a functional map can operate like a function. Depending on the type of item, the result of the functional map is now returned to the invoking rule of the calling map, instead of being written directly to output. With this enhancement, the calling map can process the result of the functional map.
The enhanced functional map behavior has been backed out. The functional maps will behave as in earlier releases. A patch is available from technical support.
See APAR PM91154.