I'm having the same issue with IN Form IT-40RNR and found your post.  I dread calling customer service and hoped you had found a work-around.  My clients are Ohio residents, husband works in IN, wife has no income at all.  I've been filing them this same way for the past 4 years, with no problems.  Now I'm getting the false error on line 1B for the spouse.  Tried deleting the state return, updated software, but error still there.  If I enter $0, then I get the pop-up error message: "Form IT-40RNR: Spouse's gross income from Indiana employment should be greater than 0 since you indicated spouse worked in Indiana for more than 30 days.  Leaving the number of days worked in Indiana blank assumes you worked in Indiana the whole year."  The two-digit code numbers for county/state where you lived and worked on Jan 1, 2024 are all the same as last year.  What a pickle!