Place banners with rotations 0 to 15, /effect give @s mining_fatigue 1000000 1 true
then /gamemode survival
and break one after another. You will notice the breaking texture being repeatedly flipped horizontally on rotations 2, 6 and 14 (it's visible the most when moving your mouse while breaking; 10 is not flipping) and displaced on rotations 1-3, 5-7, 9-11 and 13-15 (visible mostly when a banner is moving).
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Confirmed, here's banner 14 as an example:
[media]Can confirm in 20w46a.
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w06a.
Can confirm in 21w13a.
Can confirm in 1.17.
Can confirm in 1.17.1.
Can confirm in 1.18.
Can confirm in 1.18.1.
Can confirm in 1.18.2.
Can confirm in 1.19.
Can confirm in 1.19.2.

Can confirm in 1.19.3.

NeoForge BG: https://github.com/neoforged/NeoForge/pull/26
Please attach a screenshot of the banner texture with your F3 Debug screen enabled