Unlocking a task causes Orchestrate to temporarily lose all its pegging links to/from that task (until you manually trigger Repair Pegging Links). I can confirm that it is a real (albeit temporary) loss of pegging links rather than a graphical glitch. I can zoom in/out, change task selection, etc. It remains unpegged until I do something that triggers a repair (e.g., drag/insert tasks, save/refresh the plan, click Repair Pegging Links, etc.) Meanwhile, the Material Requirements panel and the Prod/Usage tab all show incorrect information (e.g. values in Unplanned column for components that should be pegged).
The pegging links functionality has been enhanced in Orchestrate version 7.67. Please upgrade to this version or above.