Template suggestions periodically not being recognized I have some simple template suggestions setup in my THEME_preprocess_node() function. Example:

function my_theme_preprocess_node(&amp;$vars) {
  if ($vars['node']-&gt;type == 'MY_TYPE' &amp;&amp; $vars['view_mode'] == 'MY_VIEW_MODE') {
    $vars['theme_hook_suggestions'][] = 'my__template';
  }
}


Then I have the template file (named my--template.tpl.php) setup in my theme. I cleared the cache, and this is recognized right away and works fine.

Then, after about an hour, if I refresh the page that uses the template, it suddenly is not recognized anymore. I clear cache again and it comes back.

Has anyone experienced this before?

Just FYI, I am using hook_theme() in a custom module to specify the theme for this page based on the URL alias.
Turns out I had the wrong hook specified. I copied this from another theme and forgot to update the hook prefix. So I had:

other_theme_preprocess_node


instead of:

my_theme_preprocess_node


Changing that seems to have resolved the issue.