I have experienced the same thing - iOS (iPad) - a few days ago I created a series of notes, and when I went to another device later in the evening, the notes were nowhere to be found. Back on the iPad, gone.
Again today, with a bit of hesitation, I created one new note on the ipad, did a manual sync, and it appeared all was OK. Tonight, checking on another device, it is gone (and also on the iPad). I get the sense that even when the iOS appears to be synching, the message is actually not getting back to the database in the cloud.
Evernote IS my workflow across multiple devices all day long. I suddenly cannot trust the iOS at all. Gulp.
In a similar vein, the web clipper on iOS now pops up with a message that 'this note will sync with Evernote on this device the next time the app is opened - it may take a few minutes" (something like that). So now to get a web clip to 'phone home' the app has to be opened first. Maybe a small thing, but it really bogs down efficiency (and sync, when it works, is really slow).
I am all for the unification of the platforms and parity, but the wheels feel like they are coming off right now.