Arison

I live in a class 3 city in MO, and we have 8 council members for 4 wards. There was a motion brought up and unfortunately there were only 6 council members there. The motion came to a tie, but the mayor said he was unable to be the tie breaker due to there not being a quorum. Is this true? If there was not a quorum how was a council meeting even held? I am very confused about this and would greatly appreciate any help given. Thank you!