lights stuck on

hi all,

have a problem with three desk channels being stuck at 51%.
the programmer was empty, there was no active cue lists, one page only, and everything off except the GM and wing master. . . . . . .and the lights where still on.
I could control them in the programmer and/or the cue they where a part of, but as soon as I hit clear or release (even PIG+RELEASE) they jumped back to 51%

any ideas why? and more importantly, how to turn them off?
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