Parse error in some posts in a WP Multisite Installation

I am running a multisite installation with several sites on their own domain, using the same theme.

Nevertheless, on this site: something weird is happening.

Some of the posts open properly, such as:

But some of the posts are giving me an error, such as:

The error is "Parse error: syntax error, unexpected $end in /home/storage/2/1e/41/ogerente/public_html/wp-content/themes/magazine/page.php on line 1"

First, I don't understand why some posts open up properly and others don't.

Second, I tried changing the URL of a post that had this problem, and now it works normally ( As you can see, I added e "-1" in the end of the URL to make it work.

Third, this exact same theme is used in other sites in this multisite installation, and there is no problem at all with these sites (ex. and All posts open up normally.

Any ideas?