I'm no tusre if this is help, but I have had issues with my TN55 (shuttle clutch) intermittently doing something similar. It has been doing it for a long time now, and I have worked out a method to combat it.
On start up, ~30-40% of the time I get a warning light (flashing amber gear light as I recall) when I put the direction of travel lever in gear (sorry, it may be after I start it and before I move the lever; really all it does is control the direction of travel that the clutch locks up in). This eventually transitions to a flashing red light (the 'read your manual and do what it says' light). If I waited for ~90 seconds or so, then re-engaged everything it would still work, but with the flashing manual lamp lit.
I finally figured out a few months ago that if I give it some fuel and get the alternator lamp off (and a bit more) that I don't have this problem anymore. I think mine was simply a low flow error due to cold start up, though the codes indicated another issue (trans or range gear selector issues -- even though the switches and wiring all looked good and ohmed out).
Good luck on yours!