Known issues in Templating

The following list describes issues that are known to exist in templating functionality.

The following bugs are known in Templating and in the Template Builder application:
Using both template-based publishing and templateless, data-only publishing with the same content can lead to unwanted side effects
Tridion Sites offers two methods of publishing: template-based publishing and its replacement, templateless, data-only publishing. While you are migrating from template-based publishing to templateless, data-only publishing, you may find yourself considering using both methods at the same time for the same publication.
However, doing so requires you to use two different publishing pipelines side by side, with extra total cost of ownership to maintain.
Beyond those organizational costs, there are also technical issues that can arise. For one, the Content Delivery search feature is designed to be used with templateless, data-only publishing only. For another, an instruction to Content Delivery to remove a Component results in all of that Component's information being removed, whether rendered with template, or publishing without a template (JSON content), when unpublishing a Component Template.
For all of these reasons, you should not mix the two publishing methods when handling the same content.
You can save a Template with empty mandatory parameters
Template Builder allows you to save a Template even if you left a mandatory parameter in one of its Template Building Blocks empty.
Warnings with parameters from removed Parameter Schema set
If you remove a Parameter Schema that is being used by a Template Building Block invocation in a Template, and you specify values for the parameters in your template, Template Builder shows warnings but will run normally. To get rid of these warnings, edit the Template directly in Content Manager Explorer and remove the parameters that cause these warnings.