Compile Error: Cannot use isset() on the result of an expression (you can use "null !== expression"

[ana777]

Please HELP

 

I have the following error on a prestashop 1.7 version when I click in the TopMenu navigation. Everything else seams to work OK. 

 

FatalErrorException in 8bcd7270a031099175bfb93bc8750d28a0a5755b.file.category.tpl.php line 308:

Compile Error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead)

 

Does someone knows how to fixe it? Its URGENT!!!