Greeting everyone

We migrated customer from Websphere MQ6 to MQ7 and we starts seeing customer channel encounters sequence number error on MQ7. After we fallback customer to MQ6, no error seen, we do not think any connectivity issue.

After reviewing MQ7 log, been seeing below error AMQ9002, AMQ9526 & AMQ9999.
AMQ9002: Channel 'ABCDEFG2.ATLTYBP1' is starting.
AMQ9526: Message sequence number error for channel 'ABCDEFG2.ATLTYBP1'.
AMQ9999: Channel program ended abnormally.

Nothing changed at customer end, so, i am fairly sure it is our Websphere upgrade to MQ7 that caused the message sequence number error.

Could it be message synchronization problem on MQ7 ? Bug ?

Any suggestion or experience to share is highly appreciated.