Flickering occurs when foliage comes into contact with defective blocks. For example: fence, hatch, step, anvil, scaffolding.
Steps to reproduce:
Place any leaf block beside any of the blocks listed below.
List of affected blocks (may be incomplete):
Stairs (any side)
Beacons
Glass/panes
Pistons
Anvils
Iron bars (MCPE-168603)
Enchantment tables
Scaffolding
Fences
Walls
Carpets
Slabs
Doors/trapdoors
Item frames
Brewing stands
Beds
Composters
Chests
Lecterns
Decorated pots (MCPE-176297)
Banners
Day/night sensors
Portal frame
Hoppers
Grindstone/stonecutter
Azalea (MCPE-121882)
Mangrove roots (MCPE-153720)
Dripleaves (MCPE-129129 MCPE-123733)
Linked issues
is duplicated by 1
relates to 1
Attachments
Comments 3

Relates to MCPE-153720
Can confirm, affects 1.21.50. This issue affects all leaf variants. The main group of blocks that cause z-fighting with leaves appear to be transparent, non-full blocks. Transluscent blocks and powdered snow are being tracked at MCPE-169629.
Steps to reproduce:
Place any leaf block beside any of the blocks listed below.
List of affected blocks (may be incomplete):
Stairs (any side)
Beacons
Glass/panes
Pistons
Anvils
Iron bars (MCPE-168603)
Enchantment tables
Scaffolding
Fences
Walls
Carpets
Slabs
Doors/trapdoors
Item frames
Brewing stands
Beds
Composters
Chests
Lecterns
Decorated pots (MCPE-176297)
Banners
Day/night sensors
Portal frame
Hoppers
Grindstone/stonecutter
Azalea (MCPE-121882)
Mangrove roots (MCPE-153720)
Dripleaves (MCPE-129129 MCPE-123733)