When uploading a mesh and moving the mesh uploader preview camera, any HUDs that use llWorldPosToHUD become offset from their correct positions.
After closing the mesh uploader, the offset persists. The only way to fully resolve the issue is to relog. Zooming out in the mesh uploader preview can make the HUD appear closer to the correct position, but does not fully fix the problem.
This issue has been occurring for approximately a year, I only just identified the mesh uploader as the cause.
Expected behavior:
HUDs using llWorldPosToHUD should remain correctly aligned regardless of interaction with the mesh upload preview.
Actual behavior:
HUDs become permanently offset after moving the mesh uploader preview camera until the user relogs.
Viewers affected:
  • Second Life Viewer
  • Firestorm
  • Alchemy