Hi Alexa,
I recommend reaching out to support for recommendations on how to resolve your ongoing discrepancies. There is no specific limitation on the number of times you can request a background sync, but keep in mind that this process is manual, and would need to be requested on a one-off basis.
Most likely the underlying replication issues could be resolved through adjustments to your replication methods or recheck settings, and support can help guide you in making these adjustments.
Chris Schmid
Sr. Product Analyst
Adobe