Working with managed metadata is a key component of SharePoint. To make it work properly we need to set up the taxonomy structure through the Term Store Manager application in the SharePoint Administration site. It is very important to know how the data is updated so that it is ready to be used in the rest of our tenant or a particular Site Collection, to avoid any kind of confusion and frustrations.
As Term Store administrators, whether we want to create a taxonomy structure at tenant or site collection level for managed metadata fields or for navigation, any changes we make in the Term Store are reflected and stored in an internal SharePoint list you may know already, the Taxonomy Hidden List. This list, located at “[Site_Collection_URL]/Lists/TaxonomyHiddenList”, should be synced with the Term Store, otherwise, we won’t see consistent data in list views, web parts, and so on, unless we are editing an item through the edit form, which takes the values directly from the Term Store.
You may find that this synchronisation is not always as fast as you wish or even seems to not work at all. The reason for this is that there is a timer job called “Taxonomy Update Scheduler”, which handles this synchronisation between the Term Store and the Taxonomy Hidden List. After this synchronisation, the list will be indexed just like any other list or library in SharePoint. You may already know about this timer job if you have worked with SharePoint On-Premises before, but it is also used in SharePoint Online.
So, if we edit the Term Store, we must take into account that it can take up to 24 hours for the “Taxonomy Update Scheduler” timer job to be triggered and synchronise the Taxonomy Hidden List, and even with that done, the list must still be indexed. If after 24 hours checking the Taxonomy Hidden List hasn’t sync, we should be concerned and raise a ticket with Microsoft to understand if there is a problem with the service.
Currently, in SharePoint Online, there is no way to force the timer job execution or any kind of workaround, since we don’t have control of this timer job which is managed by Microsoft, so being aware of this process is important in order to get better control and management of the Term Store and to understand potential timing issues.