UPDATE:.. I have just completed 8 shots with just the 1.4 on....same settings, 800 asa....... ranging from 6 to 20 min....and I can't replicate the error !!!!....all the images show no indication of the problem I was having!!.... I would have been happy to confirm that the error was still there.....but now I just don't know at all....
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....I'm off to bed....my head hurts...