LPS-43065  The pages of users which created by a site template are missing after importing the site template from other environment

The root of the issue is after import site template(imported site template's LayoutSetPrototype is not in the current environment), program didn't update layoutset table.

Refer to import page template's logic(lartype="layout-prototype") to fix the issue.

In doImportLayouts method of  LayoutImporter.java,
// 322 line 
if (group.isLayoutPrototype() && larType.equals("layout-prototype")) {
   if (existingLayoutPrototype == null) {// refer to the logic to update layoutset table}
}

Thx,
hai