Says Transaction not executed but the funds still went through

If the transaction went through and everything is working as expected then there is more likely a bug in the Mist wallet.

Please raise an issue on their Github repository.

However, I did find similar users who have had the same issue as you. In short, their advice is:

Delete the whole database and start synchronising everything again. It then works.

Please see the following issue for more information: Issue 1408

Hope this helps.