Take 2 on last, a=chris

diff --git a/src/controllers/CrawlController.php b/src/controllers/CrawlController.php
index 59f8009e1..d3c3f4f72 100644
--- a/src/controllers/CrawlController.php
+++ b/src/controllers/CrawlController.php
@@ -249,7 +249,8 @@ class CrawlController extends Controller implements CrawlConstants
                 ($lookup_info[0][0] === 'h'
                 || $lookup_info[0][0] === 'r'
                 || $lookup_info[0][0] === 'g') ||
-                strncmp($lookup_info[0], "cache:", 6) == 0) {
+                (is_string($lookup_info[0]) &&
+                strncmp($lookup_info[0], "cache:", 6) == 0)) {
                 $our_lookups[$lookup] = $lookup_info;
             } else {
                 $our_lookups[$lookup] = [];