Using TEXT_ICON(“”) in a thumbnail column will show a broken image. It was working.
@Steven_Aung
This is a known bug and developer team was working on that lately
[Text_Icon is not working](https://community.appsheet.com/t/text-icon-is-not-working/8928/9) Questions
@Wes_Bunch As a workaround, you could convert it as a text.