Strange things happening with Hierachy Fixture Groups

Happy new year. Just a quick Query with Augment 3D. Spent the best part of a day adding in all my measurements for the theatre, got all the walls, ceilings, stage and so on spot on, and finished adding and positioning all 150 fixtures. I grouped the fixtures into group so - LX bar 1 - and placed the relevant channels in that group.
I saved and shut down, and came back this morning to find my fixture groups in the Augment 3d Hierachy had changed to a 'patch node', and had lost the name. I have watched all the relevant help tutorials but I can't see why. Can anyone shed some light on it? According to the tutorials I can place the fixtures into groups in the hierarchy and they should stay there...