I had one like that earlier this year.  Client found out her husband was doing a little moonlighting, along with a little drinking, plus  I think she caught him jaywalking one day.  He doesn't want to report the income (no 1099, so no income), and she wants a divorce and to file separately.  Nine months later, she is willing to forgive the jaywalking and he decides to report the couple of bucks he made and they decide that they can't live without each other and really want to file a joint return for 2019 since he never filed a return.  Sometimes dealing with clients is like watching a soap opera. 😕