The success of developer forums like Stack Overflow (SO) depends on the participation of users and the quality of shared knowledge. SO allows its users to suggest edits to improve the quality of the posts (e.g., questions and answers). Such posts can be rolled back to an earlier version when the current version of the post with the suggested edit does not satisfy the user. However, subjectivity bias in deciding either an edit is satisfactory or not could introduce inconsistencies in the rollback edits. For example, while a user may accept the formatting of a method name (e.g., getActivity()) as a code term, another user may reject it. Such bias in rollback edits could be detrimental and demotivating to the users whose suggested edits were rolled back. This problem is compounded due to the absence of specific guidelines and tools to support consistency across users on their rollback actions. To mitigate this problem, we investigate the inconsistencies in the rollback editing process of SO and make three contributions. First, we identify eight inconsistency types in rollback edits through a qualitative analysis of 777 rollback edits in 382 questions and 395 answers. Second, we determine the impact of the eight rollback inconsistencies by surveying 44 software developers. More than 80% of the study participants find our produced catalogue of rollback inconsistencies to be detrimental to the post quality. Third, we develop a suite of algorithms to detect the eight rollback inconsistencies. The algorithms offer more than 95% accuracy and thus can be used to automatically but reliably inform users in SO of the prevalence of inconsistencies in their suggested edits and rollback actions.