Do you always believe it?

So I sometimes do walmart pickup and today I did my pickup and before I got there, three items were "out of stock" on my list. No biggie. It has happened before. Before I got to the pickup area, I had already realized I forgotten two things on my list and decided to quickly go in and get them. (I actually had time today) Well there were two out of stock items on my list near where I had to go...and low and behold...those items were right there. Yes I didn't get charged on my pickup, but I find it kind of odd that they would put that they were out of stock. Has this ever happened to you?