A variety of reports have taken issue with the pardons issued.
First reports were only about the four trustees who had worked at the governors mansion. That kind of work generally gives prisoners quite a lot of freedom, and under normal (expected?) circumstances might have given the gov some opportunity to decide they were demonstrating rehabilitation that might merit a pardon, but the (ex) gov didn't really seem to know who they were when he made his first public defense about the protests.
It has since been found that (as noted above) he did sign approximately 200 pardons at what appears to have been an exceedingly hasty "last minute action."
The State Attorney General has noted that the majority of the writs lacked "significant and substantial" elements normally required in such documentation of a pardon. As an example, he cited the failure to include a description of the offense for which they were jailed (and thereby, lack of any legal definition of what offense was pardoned).
The ex gov (and/or his office) have claimed that he acted "on advice of the State Parole Board," but a significant percentage of those pardoned apparently were not eligible for parole and thus it may be assumed that the Parole Board had never seen nor heard of them.
Various State Agencies, including the AG office, the courts, and the State Legislatures are "investigating" whether any laws were broken - indicating fairly persuasively that nobody in Mississippi has much knowledge of what the laws are.
The whole situation smacks of a celebration of the end of the ex gov's term, quite possibly at a party with a liberal amount of "shine," after which someone shoved lots of papers in front of him and he signed whatever landed there. He gave every impression at his first couple of public statements that he really had no f**g idea what all he'd signed.
(of course that's only an interpretation from what they've said in the news)