Solo fader Bug?

Hello,

I programmed an acl fader as solo, for a last break in a song, for example.
So i press the solo acl flash button, to get time to set all other int faders to 0 or to rel. effects.

But, here it comes, if i stop pressin the flash button, all motorfaders on my FB4 jump into their values they had before again.......

Any ideas?!

Thanks and greets
Be