Strange page not found entries in logs

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Hi All,

I have a block on every page of the site. In the blocks view controller is some logic that inserts a line of information into a txt file. (see below).

$data = $this->BannerID.','.date('Y-m-d').',1'.','.$page_id. "\n";
file_put_contents('stats/header_ad_impressions.txt', $data, FILE_APPEND);


It inserts the page id as the last bit of information. This is all working fine. All the variables are correct and writing to the file without issue.

When I checked after the weekend the log file had were all correct but it also had lots of additional entries with the page id as 117. This is the page id for page not found..?

Can someone shed some light as to why this maybe happening please..?