When I say it is doing nothing, it is doing nothing.  No number appears on Line 25 (Excludable Benefits) and no number appears on Line 26 (Taxable Benefits).

Note that the client did not have any DCB deductions on current year W-2, so this result would be fine if there were no carryover benefits from 2021.  But there is, I have entered the amount on Line 13, but nothing changes after I have done that.