same product in different category shows out of stock

[mith]

Hi i have  installed  magento version 2.1.0  with default luma theme. i have created some category and added some demo products. my problem is that  same product with enough quantity is showing in stock for one category and out of stock in another category. when i short it by name  or price it change from out of stock to in stock. and after refresh the page again shows out of stock. this is not good. 

My website url is :  http://strictl1.nextmp.net/mag2sd

You can check the error on these two category links

http://strictl1.nextmp.net/mag2sd/laminate-floors.html   and   http://strictl1.nextmp.net/mag2sd/vinyl-floors.html

Check for the product titled Second Products