1. Update/render viewport in a file containing workgroup reference of model file 2. Notice a wall join that's become disconnected 3. Go back to model file and rejoin wall (despite the join looking perfectly fine in the model) 4. Go back to workgroup reference file and update workgroup reference 5. Re-render viewport 6. Notice that join looks fine now, but another wall join has become disconnected (usually at the other end of the said wall) 7. Go back to model file a