The block material for the copper grate should be 'alpha_test', not 'blend' because the textures of copper grates are not semi-transparent.

MCPE-176366 and picture below shows the block material is set to 'blend'.

This bug is easy to solve: Changing the copper grate's block material to 'alpha_test'.

Material 'blend' is making bug: MCPE-130262(Banners render in front of transparent blocks).
This bug isn't duplicated to MCPE-130262.
This bug is just explaining that the copper grate has blend material, NOT explaining Banners render in front of them.

Steps to reproduce:

1. Enter a world.
2. Place campfire
3. Place copper grate wall in front of the campfire.
4. Watch.