I have noticed some strange numbers recently too. Here are two examples:

The most recent was on a ticket I purchased last week. The payment total section was $2,239.61 which was the sum of the fare details plus the taxes/fees/charges less a promotion value. So far so good and that's the amount I paid. Then I called to apply a GUF using A class and the ticket was reissued the following day showing a payment total of 0 (not surprising as there was nothing extra to pay) but the fare details now shows a total of $3,250 - $3,250 = 0. Where did the $3,250 come from?

The second example is the most bizarre. This relates to a redemption using a Chase Travel Together ticket. For some reason the taxes/fees/charges were not collected when I booked it and no ticket had been issued so I called up about 10 days before departure, paid the outstanding amount which was $1,604.00 for two people and waited for the e-ticket which arrived the same day. However, the e-ticket shows the following:

Payment total $2,895.05
Fare details $0 + tax/fee/charge $4,186.10 = $4,186.10

I have no idea where the figure of $2,895.05 or the figure of $4,186.10 comes from. Any clues anyone? We paid a total of $1,604 + Avios for one + Chase Travel Together.