I am working on a model in large assembly mode, everything is nice and defined, when I go into the drawings I look at the tree and there is a lot of over defined marks.  I re-open the model and notice that one of the suppressed assemblies has become unsuppressed and is conflicting with some of the other assemblies.  This happens several times during a job and I'm wondering why assemblies become unsuppressed on their own?  If I delete the assembly in question that works but I am trying to avoid doing that as I may need to re-use this file later for another job.  Any advice would be greatly appreciated.