#3420565 : your yellow trace is correct, green merger. You were TB-er, second player added merger and system added that wrong trace and rejected yours (wrongly), 3rd player played as you, and system said, "ok, this is correct now*…
#3420552 is a fused merger: AI overcolors a lot into wrong neuron. Your red/ my green in following pic. I marked where it overcolors. When overcoloring is as bad as in this case - wrong part reaches edge of cube and would spawn wrongly, we do not color, thus the empty space in overview.
#3418510 You took the wrong trace (it turned dupli, and obvious to belong in other cell). It’s again a slight overspill of the AI-coloring needing to leave a gap. Go into z-plane, there you see best which is correct trace.
(added backtrace to your coloring)
#3420555 and #3420836 it’s the same fused merger described above in first entry. Red wrong, belongs to other neuron. And you could see just looking at the pic that there something must be wrong.
#3420378 #3418529 #3419614 red correct, reaped in
Hope, i could help, you can always ask in chat, is probably faster. But do not ask after you just Trailblazed and have error (unless you suggest a merger), sometimes things correct by own after 3 players have played.