It looks like the item is sent to the server with a modified X-MOZ-LASTACK property and appears to be accepted, but when it is requested from the server again the X-MOZ-* properties are missing from the item. Without the X-MOZ-LASTACK property it appears to Lightning that the reminder was never dismissed, which causes it to re-fire.
It looks like the item is sent to the server with a modified X-MOZ-LASTACK property and appears to be accepted, but when it is requested from the server again the X-MOZ-* properties are missing from the item. Without the X-MOZ-LASTACK property it appears to Lightning that the reminder was never dismissed, which causes it to re-fire.