No court has been willing to certify a "class" for "lessors". The problem is that there are no, to this point, groups that are "exactly" identical as to their lease forms, lease language, etc. that are sufficiently numerous to make a class. Yes, they all have the same issue, post production deductions, in one form or another. Mineral lessors can bring suit individually or as a group, just not as a class. Case law gives cover to operators regarding litigation by lessors but oddly, and thankfully, not un-leased mineral owners force pooled in drilling units. There are two class actions on the docket for those suits now.
A few years ago there was a TX law firm that was hustling land/royalty owners wanting to sue CHK in NW Louisiana. I assume nothing ever happened on that.
Royalty owners seem to be having a little more success in suing operators in Ohio, from the little reading I do. If I recall, CHK got their rumps kicked in TX by the Bass brothers and others, including the operators of DFW a number of years ago. Someone has already mentioned that if one wants to take on CHK or the others, better have deep pockets for legal expenses.