When an arrow is shot, it appears invisible from certain angles.
This is in a vanilla large-biomes world created in 1.21.4 that has not been modified in any way, aside from two resource packs, one that changes most GUI's to a darker color, and one that changes the skybox. Removing the resource packs does not resolve the issue.
Thank you for your report!
I am not able to reproduce your issue, the arrow on my side is always visible, in any angle, is it possible to have a closer look to the arrow and even have the map so the community can try on their side? Also, have you tried things like restarting the game without the packs, viewing on another zone or map, or is your client modded (mods can replace vanilla textures and how the game render things)?
Anyways, it look like the arrow miss a 2D part, more pictures would be useful, i will wait for the images (and the video) and/or the map and try to reproduce it again, but for now, i think your issue can't be confirmed.