@Ja***
because it is the holder of the passport's responsibility to make sure you're stamped in for the correct amount of time I'd say you should get the stamp corrected long before you come up for an extension of stay, BUT I'll leave that up to you.
It's free to correct the stamp,at the immigration office.
Just show up, let them see that you were on an O-A visa, the date you bounced and they should correct your admitted until date to a year (minus 1 day) from the date you bounced.
Look at your original entry stamp you entered on 4th Sept 2017 and were stamped in until the 3rd Sept 2018 <- that stamp is correct.
The entry stamp you got should be date entered 7th Aug 2018, stamped in until 6th August 2019.