This could be because of an issue with the Magento Cron, to trigger the "updates" hook. Updates to the product table are synched with Tagalys automatcially, if the updates hook in Magento is triggered. We have seen this happen at a few clients either due to their Magento setup or sometimes due to server setup. To assis with this, you can use the Tagalys cron, that sends these updates 

In order to ensure updates are sent to Tagalys without using the Magento cron.  

You can let us know if this change is being made and our team will check the logs to make sure it is working correctly.