If above is true, with soap bubbles seen at outlet of valve, then the seat(Item 10) is leaking. Replacing gland packing/ring(Item 3 & 8) is not correct if no soap bubbles is forming at the purple arrow area.
As 4 valves have been indicated in reports to have this issue, I have the replacements spares send to GMS by next Monday. Once the spares arrived into Thailand, then I will arrange for my representative to go over and check the seats of the 4 existing valves and do any replacements if required.