Presumably this is from a config of something like?

$wgDebugLogGroups['redis'] = '/var/log/mediawiki/redis.log';

Or is it a different DebugLogGroup?

worthRefreshPopular comes from WANObjectCache, and is a debug warning

		$this->logger->debug(
			"worthRefreshPopular($asOf, $ageNew, $timeTillRefresh, $now): " .
			"p = $chance; refresh = " . ( $decision ? 'Y' : 'N' )
		);

Maybe you just want to tune the logging level you're sending to file...

Possibly a question for @aaron if that needs to stay as debug or can be downgraded to info

I've changed the log level to warning, thanks! (figured that out after writing this).