For each synchronization, you can configure an advanced property *sync.outgoingInterval* to define how often Backbone should check for new changes in a Jira project. Based on this check, Backbone identifies which changes need to be synchronized. In order to execute this and reduce the load on Jira, Backbone is telling Jira the timestamp of the last check for new changes. This timestamp is saved in the database.
This update of the timestamp can cause problems if a huge number of synchronizations are running at the same time and they always update the data.