Process may be a verb or a noun. In early texts on computers the workings of the machine was sometimes described as the workings between a processor and a processee, (the thing that processes, and the thing being processed). A common way to describe it was
The processor is called a CPU (short for Central Processing Unit), and the processee is called a process
"Processor" was absorbed as a noun in the dictionary to mean a CPU (Central Processing Unit), "processee", however, was not absorbed. Perhaps because it was thought to be sufficiently close to "process"? Whatever the reason, suddenly there were two words in circulation that meant the same,
- process (singular), processes (plural, pronounced with a short last e), and
- processee (singular), processees (plural, pronounced with a long ee);
but only 'process' was in the dictionary. In time the auto-correct revolution won, or whatever the cause was. The fact of the matter is that, except for a few books that still talk of the processor and processees, in writing only 'process' and 'processes' have survived. In speech, however, 'processees' to this day lives a happy and merry life in disguise as 'processes', and both pronunciations are considered perfectly valid ways of pronouncing 'processes'.