diff --git a/php_phongo.c b/php_phongo.c
index fb91652f5..942910d07 100644
--- a/php_phongo.c
+++ b/php_phongo.c
@@ -1110,23 +1110,29 @@ static bool php_phongo_apply_rp_options_to_uri(mongoc_uri_t *uri, bson_t *option
 		mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_SECONDARY_PREFERRED);
 	}
 
-	if (bson_iter_init_find_case(&iter, options, MONGOC_URI_READPREFERENCE) && BSON_ITER_HOLDS_UTF8(&iter)) {
-		const char *str = bson_iter_utf8(&iter, NULL);
+	if (bson_iter_init_find_case(&iter, options, MONGOC_URI_READPREFERENCE)) {
+		const char *key = bson_iter_key(&iter);
+		if (BSON_ITER_HOLDS_UTF8(&iter)) {
+			const char *str = bson_iter_utf8(&iter, NULL);
 
-		if (0 == strcasecmp("primary", str)) {
-			mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_PRIMARY);
-		} else if (0 == strcasecmp("primarypreferred", str)) {
-			mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_PRIMARY_PREFERRED);
-		} else if (0 == strcasecmp("secondary", str)) {
-			mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_SECONDARY);
-		} else if (0 == strcasecmp("secondarypreferred", str)) {
-			mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_SECONDARY_PREFERRED);
-		} else if (0 == strcasecmp("nearest", str)) {
-			mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_NEAREST);
-		} else {
-			phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT TSRMLS_CC, "Unsupported readPreference value: '%s'", str);
-			mongoc_read_prefs_destroy(new_rp);
+			if (0 == strcasecmp("primary", str)) {
+				mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_PRIMARY);
+			} else if (0 == strcasecmp("primarypreferred", str)) {
+				mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_PRIMARY_PREFERRED);
+			} else if (0 == strcasecmp("secondary", str)) {
+				mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_SECONDARY);
+			} else if (0 == strcasecmp("secondarypreferred", str)) {
+				mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_SECONDARY_PREFERRED);
+			} else if (0 == strcasecmp("nearest", str)) {
+				mongoc_read_prefs_set_mode(new_rp, MONGOC_READ_NEAREST);
+			} else {
+				phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT TSRMLS_CC, "Unsupported %s value: '%s'", key, str);
+				mongoc_read_prefs_destroy(new_rp);
 
+				return false;
+			}
+		} else {
+			phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT TSRMLS_CC, "%s URI option expected to be string", key);
 			return false;
 		}
 	}
diff --git a/tests/manager/manager-ctor-read_preference-003.phpt b/tests/manager/manager-ctor-read_preference-error-004.phpt
similarity index 75%
rename from tests/manager/manager-ctor-read_preference-003.phpt
rename to tests/manager/manager-ctor-read_preference-error-004.phpt
index 48a2624f8..668ec04ce 100644
--- a/tests/manager/manager-ctor-read_preference-003.phpt
+++ b/tests/manager/manager-ctor-read_preference-error-004.phpt
@@ -1,5 +1,5 @@
 --TEST--
-MongoDB\Driver\Manager::__construct(): read preference options of the wrong type are ignored
+MongoDB\Driver\Manager::__construct(): read preference options of the wrong type will not be ignored
 --FILE--
 <?php
 
@@ -12,17 +12,19 @@ $tests = [
 foreach ($tests as $test) {
     list($uri, $options) = $test;
 
-    $manager = new MongoDB\Driver\Manager($uri, $options);
+    try {
+        $manager = new MongoDB\Driver\Manager($uri, $options);
+    } catch (MongoDB\Driver\Exception\InvalidArgumentException $e) {
+        echo $e->getMessage() . "\n";
+        continue;
+    }
     var_dump($manager->getReadPreference());
 }
 
 ?>
 ===DONE===
 --EXPECTF--
-object(MongoDB\Driver\ReadPreference)#%d (%d) {
-  ["mode"]=>
-  string(9) "secondary"
-}
+readPreference URI option expected to be string
 object(MongoDB\Driver\ReadPreference)#%d (%d) {
   ["mode"]=>
   string(9) "secondary"