Today, Bob Ward at Microsoft posted an blog post on the CSS SQL Server Engineers blog that provides some explanation of a Connect Item I filed earlier this year regarding partial XML information in the ring_buffer target.
You may not see the data you expect in Extended Event Ring Buffer Targets….
If you use Extended Events or have plans to, give this a quick read, because it will impact which target you consider using, or how you go about configuring one of the in memory targets should you use one.