Can you be more specific.  What is the guarantee that you haven't typed
M-l, M-u or M-c?

> I have not customized dabrrev ... I believe I run into this
> accidentally when I type in some control/alt combinations
> inadvertently.
>
> Regards,
> Kashyap
>
> On Thu, Jul 19, 2012 at 7:34 PM, Jambunathan K <
> kjambunathan@gmai...> wrote:
>
>     C K Kashyap <ckkashyap@gmai...> writes:
>    
>     > Hi,
>     >
>     > I noticed that at times when I do a M-/ and try to complete a
>     word
>     > that already exists in the buffer (I assume, this is what I
>     need to
>     > do if I need to do what I did using C-p or C-n on vi), the word
>     > completion happens but with weird casing. Sometime all caps
>     etc. I
>     > wonder if there is some setting I need to do when I get into
>     this
>     > situation.
>    
>     Have you customized dabrrev?
>    
>     See (info "(emacs) Dabbrev Customization")
>    
>    
>     >
>     > Regards,
>     > Kashyap
>     >
>     >
>    
>     --