I recently purchased Bitcoins and transferred them to Multibit. When I went to then transfer them to CEX.Io, it then said something like pending on Multibit. I then click the link to blockchain and it says something like invalid. So i go back to Multibit and CEX.io to see if my balance has been sent to either one, and it was not.
I had that with electrum yesterday. Said pending for an hour or so ..... must have been some cheese in the network or something. Longest 3-confirmation time I have ever waited for, and yes, I did pay the normal fee.