Alright, so for the action_session_start not triggering, it was because you needed to retrain a new model after overriding the default action_session_start. Everything else with action_session_start looked good fine
As for the Telegram question it seems others have mentioned this as part of the functionality – I haven’t used Telegram all that much, so I can’t say for sure, but from a quick search around, telegram might send /start? If that’s the case, you have to add this to your domain.yml's intents:
- start:
triggers: action_session_start
as well as a matching story:
## telegram sends start message (mapped action)
* start
- action_session_start
Take that with a grain of salt, though, I’m not 100% sure that’s how Telegram handles it, so YMMV.