To have a more reliable contact synchronization we suggest setting it up to CDC.
In order to do so you'll need to make a few quick changes in your Salesforce org to begin with.
Log into your Salesforce account and in the upper-right corner click on your avatar and then click on "Setup".
Type in the quick find box on the left panel "Change data Capture".
From the "Available Entities" you'll need to pick Contact, Account, and Lead an add them to the "Selected Entities".
For existing orgs that already have to contact sync running, in order to avoid any issues we suggest to notify us in advance to [email protected] so we can coordinate and change the method from our side as well.
Once we confirm for our side that the update has been done, you’ll need to run the contact sync again.