So many PLOT HOLES in this filler, i'd be totally ashamed of this:
1- Uchiha at the begining of times didn't have Konoha headbands.
2- The Uchiha using Izanagi get their eyes coloured blind-white (this is from Izanami), instead of getting them sealed (Izanagi).
TOTAL FAIL
Eh, Izanagi eyes were never confirmed to be sealed, they just always shut because that's how Kishi chose to depict blindness. True, we've never seen them turn white before closing, but it wouldn't be too much of a stretch for the whiteness to happen gradually compared to Izanami.
At any rate, with Itachi, Kishi probably felt it was more dramatic for the eye to turn white while wide open. Also, Itachi already closes one eye to perform various Mangekyou abilities, so simply closing one eye wouldn't signal the activation of Izanami as clearly to readers.
Kishi would probably have done the same thing if Itachi had used Izanagi, but then the "surprise" factor of the Izanagi jutsu is in learning is been used after the fact at the most dramatic moment, whereas Izanami has a clear starting point followed by build up, culminating in an activation once the technique is complete. Thus, the suspense is all in the signals, so an eye turning white serves his purpose.
It's probably no more complicated than that, and hardly a plothole. If the animators chose Kishi's newer, more distinct and dramatic method of showing Izanagi/Izanami blindness, who can blame them?