Buyer pays shipping-now says free shipping after sale

[dgss396]

I had a buyer email me today and said: I just went to pay for my items and it's showing a shipping charge of $6.50. Items were listed with free shipping there should be no shipping charge on this????”
I checked both and sure enough, they said free shipping.
I had sent him a combined shipping invoice for the 2 auctions he won earlier. 
he sent a item # link and it has the item clearly displaying buyer pays $6.25 shipping. I wound up giving him free shipping because the items now say free.
WHAT IS GOING ON HERE?
I took a screenshot of the ad showing shipping charge

[dgss396]

It seems there is a glitch between the phone app and the full site.

ebay owes me $4.90!

[eunster1313]

It's been a known issue with the phone app for years now that never seems

to get fixed. Sometimes it falsely shows the buyer free shipping on the listing

when it is not. The buyer will get charged and blame and get upset with the seller.