Lookup column is not showing newly added items in target list dropdown

Hi SP Gurus,

In our SharePoint online site newly added items are not showing in target list dropdown. I have dropdown named Hospitals which is a lookup column from Hospital list. Now I have added new items in lookup list but these are not appearing in target list dropdown. In Lookup list column type is Single line of text

After doing some testing I founded that we are facing this issue in one of site which is converted to classic for some reason. Newly added item is not showing in target list.