the regular bitcoin saigon meetup group has a break this week but there are some other events coming in the next weeks.
you can follow the bitcoin saigon fb group to check when and where they are meeting the next time.

there is also another event on Sept. 15 in HCMC:
2019 Block Plus Summit SERIES III - Future of FinTech

and you can check the asia blockchain review telegram group for events in vietnam.