The following are the examples to show you the solution for the "Session State Protection Violation" error in Oracle Apex.
Resolve Session State Protection Violation Error for Display Only and Read-Only items
In the below example, it will set the page item
document.getElementById("P3_COMMISSION_PCT").readOnly = true;
Resolve Session State Protection Violation Error in Oracle Apex for Hidden Items
For the Hidden page items, set its Value Protected Property to No or Turn off the switch. As shown in the below image:
Oracle Apex: Display Custom Error Messages from PL/SQL Process