The 'recently viewed' has more than 50 records per entity, causes slow performance

Hi,

We have on-premise 2016 installation where we are noticing RecentlyViewedEntityDatahas more than 50 RecentlyViewedItemitems. Due to this, len(RecentlyViewedXml)becomes very large (>100K) and user experiences overall slow performance.

SELECT TOP 100 len(RecentlyViewedXml) AS RecentlyViewedXmlLength, *
FROM UserEntityUISettings
WHERE len(RecentlyViewedXml) > 1000
ORDER BY RecentlyViewedXmlLength DESC

We have make RecentlyViewedXmlfield null & restart IIS overnight since user's browser cache populates server-side data again I guess. 

Has anyone experienced this issue & has any pointer on how resolve this.