What are common issues with loading functions in Smarty templates?

One common issue with loading functions in Smarty templates is not properly including the file containing the function before calling it. To solve this issue, make sure to include the file containing the function at the beginning of the template.

{include file="path/to/function/file.php"}
```

Another common issue is not passing variables to the function correctly. Make sure to pass the required variables to the function when calling it in the template.

```php
{$result = custom_function($variable1, $variable2)}