Calendar View using HTML link value as "Display Field" has stopped working

Calendar View using HTML link value as "Display Field" has stopped working

The latest upgrade has taken away the facility of using a formula field, which generates a HTML link code with background-color and link to HTML view, as the Display Field.

This calendar view which was working well and was used extensively by my client, now looks like shown in below..
 




While the same formula-field renders fine in list view..



Kindly fix the rendering issue in calendar views.