Maximum execution time of 300 seconds exceeded in /usr/share/zabbix/include/func.inc.php on line 1427

Randomly, php-fpm children seem to timeout (or are running an infinite loop) which brings my server to a crawl with cpu maxed out. The php-fpm www-error log shows the same function causing the issue (/usr/share/zabbix/include/func.inc.php on line 1427)...

function truncateFloat(float $number): float

{ return (float) sprintf('%.'.(ZBX_FLOAT_DIG - 1).'E', $number); }

Same issue / function call in graphs.inc.php

Any ideas why this function is timing out???