Hi Gaetano,
I had never seen this behavior, because if you have a custom process created and then you run, on the step that have the system action "lock some fields", sufficient that you updates the project and you should be able of see this change.
1 - This behavior occurs just with a specific process?
2 - The fields that are locked are all custom attributes?
2 - If you have another custom processes that have a system action "lock some fields" also this problem occurs?
3 - There maybe a CLRTxxx, but I'm not sure of this.
I've worked with Clarity v13 performing this type of lock from some fields and I had never seen this behavior, works perfect.
On Clarity 12.0, you have tried the creation of a new custom process, but this time working with subpages?, namely, they reached a certain stage of the process and then hide a specific subpage and after when you need show it again?
Regards,
Nicolas