So basically, there's .018 in an address that I should have but it isn't in my wallet. I just updated to the latest version and the problem remains.
Electrum relies on servers run by volunteers to get transaction data. Please switch to another server by clicking on the green/red orb icon in the bottom right of the electrum window. This might jolt the wallet to update your balance. Note that it'll take a few minutes to sync. You should see it say as much in the status bar in the bottom left.
Try a couple of different servers if it doesn't work. If it still doesn't work after that then restart electrum.
I restarted the client several times and it didn't work. I read this advice, opened the client to try it, and the transaction had reverted to the correct amount in my wallet and my balance was correct. So I didn't need to try switching servers.
Sorry if this doesn't help the devs out very much, but it just kind of corrected itself.
