(Note: occurs in the End dimension) Falling_block, when several of them exist at once and are either slime blocks or stained glass/panes, display all as non transparent, except for one of them, which does display as transparent. I expected all of them to be uniform in state of transparency.

Steps to reproduce:

1. Remove all other falling sand entities that may be in the world.
2. Summon several:

   /summon armor_stand ~ ~1 ~ {NoGravity:1b,Tags:["test"],Passengers:[{id:"falling_block",Block:"minecraft:stained_glass",Time:1s}]}

   and place them in an array along same y coordinate. (Also try slime blocks)
   → Notice that one of the falling sand is a transparent stained glass/slime block, while the other are not.
   → Notice that if you move further away from the falling sand, they appear like actual stained glass, but when you move closer to it, it appears like solid colors.

• It appears that raising a non transparent falling_block riding armor stand 2 blocks above the y coordinate of the other transparent falling_block causes it to become transparent and the original to become non transparent.

Note: According to Mog (Ryan Holtz) in MC-34696, "Regular glass works fine because it is alpha tested, not alpha blended. These are two different things. Alpha testing is supported on entities, alpha blending is not." However even though it is not supported, somehow one falling sand entity stays transparent as shown here.

Picture attachment notes:
2015-02-15_21.38.05.png - Slime block, lower left corner is transparent, while others are not.

2015-02-16_02.09.17.png - Stained glass, middle top is transparent

2015-02-16_02.09.47.png - Raised all of them up one block, can clearly see the single transparent glass at the bottom center

2015-02-16_02.10.13.png - Raised the c=-1 armor stand & falling sand 2 blocks up. It became transparent while the original became non transparent.

2015-02-16_15.32.25.png - Test 1 using piston extensions to maintain falling state: Top left slime block falling sand is transparent while others are opaque.