If all those who are having problems, follow the handbook instruction precisely, then there is a manufacturer problem.
However, many many people on here who are complaining about this issue have clearly stated that they believe they shouldn't need (therefore use) the start control on a warm engine.
In the handbook it states to use it, always use the fast idle control:
"To Start the Engine:
• Release the steering lock.
• Check that the engine stop switch is in the 'RUN' position.
• Insert the ignition key and turn the ignition switch to the 'ON' position.
• Ensure that the transmission is in neutral.
• Pull the clutch lever fully into the handlebar.
If the engine is cold, pull out the choke, noting the following: Above 77°F (25°C) air temperature, pull out the choke to the first position.
Below 77° F (25°C) air temperature, pull out the choke fully.
• If the engine is partly warm, pull out
the choke to the first position."
If peeps insist on operating equipment outside the manufacturers instructions, that's up to them. But surely this is not something that Triumph should be blamed for.
The only time I have ever had this issue is when I don't use the fast idle control.
Bonny - '10 Bonneville T100 with saucy Dominator pipes, de-snorkel'd, de-AI'd, UNI air filter; De-O² sensors.
2004 Jaguar S-type V8 4.2