Provide some sort of warning when using a processing pattern with a molecular assembler. Possible ways to do this (I'm sure there are others):

• Warn on the craft progress screen when a pattern is "scheduled" but unable to complete because its trying to export a processing pattern into a molecular assembler
• Warn in the interface/interface terminal screen when you insert a processing pattern into an interface which has only molecular assemblers (or nothing else that can accept processing patterns) adjacent

as an addendum to this, there should also be a warning when there's a crafting pattern in an interface that isn't touching any molecular assemblers