Order status not changeable

[Pedrolito59]

Hi all:

 

I have upgraded my version of prestashop to the latest stable version (1.6.1.14).

 

It looks like that since this upgrade, I'm not able to change the status of an order once it is delivered:

for instance, when I want to change the status from "delivered" to "refund", it gets the right status and then something moves it back to "delivered".

 

How can I detect what "process" change this status back to "delivered"?

 

Thanks,

Nicolas