As Atrios puts it, these are "truly insane prosecutors." They're so mad that their potentially-illegal death sentences were overturned by the governor -- after they had refused for years to make one iota of reform despite sending seventeen provably innocent people to Death Row -- that they're trying every technicality in the book to overturn the clemency. From the Los Angeles Times:

Indeed, by this week, prosecutors in the Evans case and dozens of others were going to great lengths to skirt Ryan's order, in some instances searching for technical legal glitches -- the kind they usually lament for freeing the guilty -- in the hope of sending some who received clemency back to death row.

They were combing old records to see if perhaps sentencing papers had not been signed or otherwise properly processed, on the theory that if an inmate had not been legally, technically, sentenced to death he could not be granted clemency from that sentence.

In several counties, prosecutors were revisiting multiple murder cases in which, after a person was sentenced to death in one or two of the crimes, other slayings were set aside. They may seek a new death penalty trial for the recently spared convict in one of the other cases. In Cook County, which includes Chicago, prosecutors filed a motion with the state Supreme Court arguing that 10 of the sentences Ryan commuted had been vacated by state or federal courts and the inmates, awaiting new sentencing hearings, should not then qualify for commutation.

See Ryan does right for more on how these self-important law-school undesirables think they have better ideas of clemency than Alexander Hamilton.