It seems that the detailTextLabel is not displaying inside TableViewCell.
I have just downloaded Samples and am looking at the Search example:
cd Downloads/Samples-master/Projects/Programmatic/Search
Install Pods:
pod install
Installing Graph (2.1.4)
Installing Material (2.6.3)
In SampleData.swift I can see that each Entity has a status:
u1["status"] = "Making the world a better place, one line of code at a time."
The status is being used in UserTableView but it is not displayed.
cell.detailTextLabel?.text = user["status"] as? String

This was a good find. I made updates to Material and the sample to fix the issue. I will update this issue once I release it from the development branch. Shouldn't be long at all.
You can find a fix for this in Material 2.7.0 :)