Is your wallet a "2FA" wallet? Does it say [2fa] in the title like this:
Or does it just say [standard]?
If it's [2fa], its probably reserving as much as possible to pre-pay for your TrustedCoin "credits" as 2FA Electrum wallets come with a service charge from TrustedCoin in addition to the normal Bitcoin Transaction fee... it is usually charged on the first send (and when you have 0 credits left), refer:
https://api.trustedcoin.com/#/electrum-helpIf it says [standard], it's possibly an issue with the default "fee calculation algorithm" in the desktop version... given that fees have increased dramatically again over the last 12 hours, it might have decided that you needed to be paying a HUGE fee and so there was nothing left to send so you could only send 0.