HSA health savings account maximum contribution

I went on Medicare in oct 2025. I thought I couldn't make any HSA contributions less than 6 months before enrollment (which would be April). Well, I did NOT make any HSA contributions early in the year, so I interpret that I lost the opportunity and can't put it in now (before filing 2025 tax return).  But working through TT, I fill in the page that says I was on HDHP family plan 9 months, and Medicare 3 months. Then the button says "calculate your maximum contribution".  and it calculates and reports back $7163. how can that be?  The maximum is $4300 + $1000 = $5300, AND what about the 6 -month limit?  Why is TT saying I can contribute $7163?

To continue, worked through the wife's info, who was on our family plan for 9 months, then individual plan for 3 months. "calculate your maximum contribution" then says ... $7163.  How and why?  And, suspiciously, when I click "calc max.." for me, the page with the answer has my name on the top.  For my wife, the page has her name at the top when I enter the monthly coverages, but when I click the "calc max" button, the table changes to MINE, with my name at the top. 

Please help.