is the pci mask persistent?

During a session of programming and working with Pin Change Interrupts. i had a strange thing occur where some of my pins were responding in pairs upon button state changes. at first i thought it could be related to the pci masks i had set so i started with clean code and just setup button events. i was still getting 2 button status going high from one button. after hours of rewriting very basic routines i decided to change the nano out. and Viola! so im certain something happened to the nano and it most likely is blown. but just to be certain i thought id ask if this is potentially related to setting mask bits. i believe they are volatile and reset up processor reset. is this correct?

mastermikie: i had a strange thing occur where some of my pins were responding in pairs upon button state changes.

If by 'responding in pairs' you mean 'button presses were being counted twice' then my guess would be contact bounce. If by 'responding in pairs' you mean 'pressing one button causes a button press to be counted for a different button as well' then my guess would be floating inputs (lack of pull-up or pull-down resistor).

it wasnt a debounce issue. i use hardware debounce. i have a register set for each button to keep its state. 2 registers were changing at once. i created a fresh sketch with just one button actually active in the loop and would still get 2 registers changing. after i changed the nano with a fresh one it was fine. so again im under the assumption its the micro itself. just strange this happened after mapping pci masks.