I have this problem with my Suzuki 3S which is basically a Martin copy. Have spoke to some people about it and it is likely due to the string gauge used and the placing of the capo. I have extra Elixir extra lights fitted and like you often play in an alternate tuning (DADF#AD).
It is quite likely that it happens because the action of my guitar has not been adjusted for the open tuning but left as it was for tuning in concert. However that said I play in both and occasionally dropped D so I just put up with it and re tune the offending 2nd and 6th strings. It also seems to help if you position the capo close to the fret.
I like you would appreciate any further enlightenment!
By clicking on the User Name, you will requery the forum for that user. You will see everything that he or she has posted with that Mudcat name.
By clicking on the Thread Name, you will be sent to the Forum on that thread as if you selected it from the main Mudcat Forum page.
* Click on the linked number with * to view the thread split into pages (click "d" for chronologically descending).
By clicking on the Subject, you will also go to the thread as if you selected it from the original Forum page, but also go directly to that particular message.
By clicking on the Date (Posted), you will dig out every message posted that day.
sj