I have solved this issue. I am not certain why this was a problem, but it turns out that best practices helped solve it in the end anyway.
Instead of running a single pg_query, I set up appropriate variables and used pg_query_params. This is probably a good idea regardless of issues.
$myQuery = "UPDATE servers SET load = load + $1 WHERE ip = '$2'"; $serverIP = '10.10.10.10'; $loadAdded = '1234'; $result = pg_query_params($conn, $myQuery, array($loadAdded, $serverIP));
Again, I don't know why this solved the issue for me, but it did.