Encountered a strange question, after switching the mailbox server, has informed the supplier (cernet), remove the old MX record and replace with a new record, and has already passed more than 10 days ago,

Recently found in 8.8.8.8 114.114.114.114 123.123.123.123 DNS on analytical record, new and old MX record will appear alternately,

And the supplier's engineer still not reason, someone had a similar problem, please? Is there a way to solve,