I submitted a "transmute" transaction (https://explorer.ergoplatform.com/en/transactions/01240eeb02b85c704c5010efce9da1206dfeb8c6f25b171b6066a4c69a5583f4) and then immediately submitted another "transmute" transaction (https://explorer.ergoplatform.com/en/transactions/e96d176f40d335337699c06ffb113dc01d466e2ec337c8bdab55a697f50973da) in the opposite direction. The first transaction was included in the blockchain. The second one was never included.