[TenTec] extra dits from Omni 6+?

[Mike J Maloney <ac5p@juno.com>]

I recently acquired an Omni 6+.  I enjoy using a bug for operating around
25wpm.  I have noticed that the rig "throws" in extra dits randomly.  
Very frustrating when I know I'm not making them.  The key is well
adjusted and does not do this on other rigs or a cpo.   There is no
problem when using an external or the internal keyer.   

Has any one else experienced this phenomonen and/or have any ideas for
the cause and solution?