Hi skimask,

There’s no program to view since it can happen with any program from a simple blink a LED to slightly more advanced stuff.
As mentioned it’s not device related since it happened with different PIC’s 16F648, 16F88, 16F688 and 16F886 if they have something common. I have tried to remove pull-ups and pull downs to no avail. The program is verified 100% OK by the programmer everytime.
I am not exactly sure what you mean by “writing over the code space”, I am a rookie and I’m not challenging the boundaries in any way (as far as I know).
The power is good and solid according to my scope and hasn’t caused any glitches before.
I haven’t tried to pull and reinstall the PIC, it’s a proto board and the programmer is permanently connected (ICSP kind).
It is connected to my laptop while I am trying out different programs.

Thanks!