What does the "&" symbol before functions in a class signify in PHP?

The "&" symbol before functions in a class signifies that the function is being passed by reference. This means that any changes made to the function's parameters inside the function will also affect the original variables passed to the function. To resolve this issue, you can remove the "&" symbol before the function declaration to pass the parameters by value instead of by reference.

class MyClass {
    public function myFunction(&$param) {
        // Function code
    }
}
```

To fix the issue, remove the "&" symbol before the function declaration:

```php
class MyClass {
    public function myFunction($param) {
        // Function code
    }
}