Hi James -
Unfortunately right now it's not possible to disable the quick-add syntax in the Android app. The iOS app follows your account settings made on the web regarding quick add syntax. We plan to make the Android app also follow your account settings - it's on our list for the next update to the app.
In the meantime, if you're typing a task where you want quick add syntax ignored, you can click the "Edit task..." button before typing the task text. On the "edit" screen no quick add parsing will be applied to what you type.
Yes, this is an extra tap, but should save you from having to clear an automatically applied date.
-Cameron