I think memcache may be truncating floats to ints, so if it is not a …

…float, cast it to and change the check to a simple is_numeric(..) one

src/Adapter/Memcached.php

@@ -22,8 +22,8 @@ public function set(string $key, float $value, int $ttl): bool
     public function get(string $key): float
     {
         $ret = $this->realGet($key);
-        if (is_float($ret)) {
-            return $ret;
+        if (is_numeric($ret)) {
+            return (float) $ret;
         }
         throw new \InvalidArgumentException("Unexpected data type from memcache, expected float, got " . gettype($ret));
     }