Charitable donation when taking standard deduction shows $300 vs $600 on Form 1040SR line 12b

Tax yr 2021

Have charitable cash donations of $860

Taking Standard deduction. Filing Jointly.

Form 1040SR line 12 b keeps showing an error.  $300 is shown for a single file vs $600 for Joint.

Have corrected it several times on the forms view but keeps going back to the $300 after I save.

Double checked charitable contribution walk through entry area. All looks OK. (The $860 I entered shows on the 1040SR form.) 

 

Why won't it correct?  Or something else I'm missing?