I have had the same problem for some time. I have found that certain Bachmann(only Bachmann) DCC locomotives cause the problem with only one particular turnout.
I only have three DCC turnouts and the only one effected is in one of three loops, so I am able to work around it fairly easily.
I only have three DCC turnouts and the only one effected is in one of three loops, so I am able to work around it fairly easily.