Here it is the script to create a table to reproduce the bug : http://pastebin.com/fXqEiZEx
Here it is the c# code to see the exception : http://pastebin.com/DtifeN7s
ORA-01008: Not all variables bound
The same code works with odp.net with OCI.
This appears to be the same issue reported in this thread: Bug: Oracle Managed Provider and BindByName
The following internal bug was filed, and the fix has been checked in. Bug 14806792: BINDBYNAME DOESN'T WORK WHEN THERE ARE MULTIPLE PLACEHOLDERS WITH SAME NAME
I don't know however if/when there will be a beta refresh that contains the fix.
Hope it helps, thanks for reporting it.