Mycelium is a bitcoin wallet app available on the iOS and Android devices, recently a bug has been discovered by the user markcoll from r/Bitcoin.
After sending a transaction if you don’t reach the final send screen or the app hangs up, after restarting the app the transaction history doesn’t update as if no transaction was sent – which makes sense. However, when trying to send a second transaction both transaction will simply disappear from your wallet and you will end up loosing those bitcoins.
The ridiculous part is that this issue has been written about over a year ago by /u/rassah:
Read More:
http://themerkle.com/mycelium-ios-suffers-from-a-major-bug-causing-disappearing-transactions/