jsonformat fails with inverse time order

[lowell80]

This fails

... 
| eval _time=if(sourcetype like "amal%", strftime(time, "%Y-%m-%dT%T.%6N%Z"), _time)
| sort - _time
| jsonformat raw order=sort indent=2

with the error message:

Error in 'jsonformat' command: The external search command 'jsonformat' did not return events in descending time order, as expected.

Most likely just the wrong Configuration options.