MC-1058 fixed indeed the issue that most entities cannot be seen when on the edge of the screen, but from my testing it seems that only applies to mobs/living entities and normal-sized blocks on ArmorStands.

On an ArmorStand with a large model on headslot though this rendering bug still occurs, both at edge of screen as well as frontal (when you look upwards), depending on block model.
Summon command for dragon head on ArmorStand headslot:

/summon minecraft:armor_stand ~ ~ ~ {ArmorItems:[{},{},{},{id:stone,Count:1}]}

It also affects self-made models, see screenshots and attached test-resourcepack by Schortan
This bug is important for mapmakers to be fixed before 1.9 release.

Two other things important to mention:
*Do not test on Y = 63* if you want to confirm it.
There is a (confirmed it by testing) bug that renders any entity (or the blocks attached to them) invisible if you're at Y= 63.
I'm not sure if this bug here can relate to it, but I'll leave the according bugpost in here to be safe, maybe you can fix it alongside this bug here:
MC-88176

*Do not test with ArmorStands that have their Marker-tag set to true*
I don't know whether or not it's "works as intended", but even regular-sized blocks vanish at certain perspective angles (sideways as well as looking up) if they're at an ArmorStand with Marker-tag set to 1. (Screenshots attached).
*It would be nice to know if this is intended behaviour* or - at least currently - not fixable, because I could think about some circumstances where it'd be nice to have an ArmorStand with Marker-tag set to true, but without the model/block "vanishing" out of sight of the player, dependant on their perspective.
*If this is maybe even a desired behaviour is up to Mojang and suggestions of the mapmaking community* - So i hope someone could comment on that.
If this is not intended behaviour and fixable, please fix it alongside with this bug.

Onnowhere opened a bugpost for this here on MC-98146

I suspect this might happen with any larger-scaled model, also selfmade models, I couldn't confirm that yet but will do so with according screenshots.
If any modelmakers read this and could test it themself with a largescale model on an ArmorStand headslot to confirm it via a comment and screenshot, I'd be very thankful }=)

Thank you.