Orders being placed for OOS products

[mikesam202abc5]

I am having my production website on Magento 2.1 CE

problem my sales team facing is they set Product to OOS (Out Of Stock ) but still the order are there for some products.

the server is AWS C5

for cache we have configured Fastly.

show OOS products in front-end is enabled so that customer can view the product but they can not add that to cart.

there are no logs into var/log & reports folder regarding this issue.

I have hired one Magento Developer to resolve this but after upgrading that to 2.4 this issue is not resolved.

[amitsamsukha · Accepted solution]

@mikesam202abc5,

kindly check sales return (RMA)  

it might be possible that some of the items are returned to you and they become in-stock again

and when the customer places the order for the item it again becomes OOS. 

[mikesam202abc5]

thanks @amitsamsukha i have checked the RMA

the items were there in returns.