What gameplay feature is this bug affecting?
purchasing from branches

What's the issue? Please include any error messages you receive and as much detail as possible.
No error message was received, which is part of the problem. I was purchasing an item off of a branch sale, and in the time between me going to the branch to purchase the item, and the transaction processing in the system, the seller had changed the price (and currency type) and the transaction was completed at the newly updated price rather than the original price without me ever being informed of the change to approve the purchase at the new price. The price change included being changed from an SB sale to a GB sale. This was not a pre-arranged transaction, so could not have been in any way an intentional or malicious action by the other player, it was just unfortunate timing. The issue is that the buyer (in this case that would be me) was never given any indication that the pricing had changed and the transaction was completed at the newly updated price without buyer approval of the new price.

Any links relating to this bug? For example, if a particular lion is bugging, what is the link to that lion?
no specific links, I don't think this is an issue that only happens on that particular player's branch or with only that specific item.

Any screenshots you can provide us with?
no screenshots available, sorry

Please provide us with step by step explanation how this bug happened so we can attempt to replicate it. If it's complex, please include screenshots where possible:
I searched for an item using the "search items" function to search branch sales. In this particular case, the item was an Angelic Blessing. I saw a listing for a low price in SB at the top of the list, and higher SB prices below it, with GB sales below that. I entered the lowest price SB listing branch by following the "visit branch" link on the search. I located the item in the shop. The price button still listed the exact SB value I had seen on search. I clicked the buy button. The confirmation message came up with the value listed the same as the listed price on the branch that I was seeing, in this case an SB value with 0 GB. I clicked confirm. A different amount was deducted from my account than I had confirmed, in this case, the transaction had also changed to a GB sale with no SB. An "item purchase" message sent to the other player listed the amount deducted from my account in GB. No screen shots available.