I don't see how rotating the prop would make any difference, based on the electrical schematics..
So I think, for now, its coincidental. At these high hours, I'd suspect something is intermittently grounding out.. though I suppose its possible a pin has finally backed out just far enough.. There's a lot going on with the starter.. knowing whether voltage is actually getting to the relay when turning the key would eliminate a lot of items to check.. But I'll try to make a list of things to check:
0. Faulty starter relay. Moving part, prone to failure. Even if it is activating, would you hear the click/clunk from inside the cockpit? Easy enough to test, but difficult if the problem has been intermittent.
0a. Ground to the engine, or wire from relay to starter isn't secure.
1. Faulty pin/wire to the ignition module. Check that the large d-sub connector is secure and that pins 8, 12, 13, 20, 25 haven't backed out of the connector.
2. At the HIC module's large d-sub connector, verify pins 3 4 7 12 13 haven't backed out, loose, etc.
2a. Possibly a problem with the 8-pin HIC module connector, if you haven't already performed the Service Bulletin on that. The original connector is known for making intermittent connections. If you haven't done SB-00058
already.. stop here and do it now.
3. Faulty relay on the ignition module board (doubtful, since the Spar Pin warning light would be ON). While you're able to reproduce the problem, holding down the Spar Pin Override button while turning the key (and it still not working), would eliminate this relay as a possibility.
4. Check the new HIC module's LED light while the starter isn't working. Note the color.