That happens some times.  It comes from your bank and there are sometimes missing or duplicate transactions.  That is why it is a must to reconcile.  http://www.artesanibookkeeping.com/exclude-transactions-bank-feed-qbo/

Resolution for 'account sync issue: 'The CIBC chequing account sync. up was missing transactions.The CIBC credit card sync. up was having duplicated transactions.' available: Yes.

The account sync issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the account sync issue yourself by looking for a resolution described in the article. If it is a complex account sync issue or you are unable to solve the issue, you may contact us by clicking here or by using other account sync support options.

For more information about resolving issues related to account sync in Quickbooks/QBO or to get support for the issue 'The CIBC chequing account sync. up was missing transactions.The CIBC credit card sync. up was having duplicated transactions.', click the link below: