Troubleshooting...
...of failed components shouldn't blindly progress past the second changed computer. Not in a fleet that has normal reliability figures for that component. I mean, what are the chances of two bad ones, let alone a third? After that the related sensors, antenae, wiring, switches etc should become the focus. Or perhaps the repair procedures.
Often a fault will be traced back to some long-forgotten part change or procedure performed just before the saga of intermittent defects started. (Always check the last thing you did)