Item frames/glow item frames can cause z-fighting in these conditions - 

• Placing almost any block on top of the item frame (z fighting can be seen from bottom of the block)
• Placing sea pickles/turtle eggs on top of the item frame 
• Placing opened trapdoor on top of the item frame
• Placing campfire/soul campfire on top of the item frame
• Placing grindstone on top of the item frame
• Placing chorus flower on top of the item frame
• Placing opened fence gate on top of the item frame in the  different direction (for example when item frame is placed facing south, you need to place opened fence gate facing west/east)
• Placing anvil on top of the item frame
• Placing lightning rod facing to the item frame on top of the item frame with some block in it
• Placing button/tripwire hook on top of the item frame with anvil/chipped anvil/damaged anvil in it
• Putting anvil in item frame
• Putting flower pot into the item frame and than placing flower pot/lever on top of the item frame (also putting lever into item frame and than putting lever on top of it causes z-fighting)
• Summoning armor stand on top of the item frame
• Summoning item frame riding some mob in some solid block
• Placing torch on top of the item frame with anvil/chipped anvil/damaged anvil in it (MC-161583)
• Placing lever on top of the item frames with block in it (MC-138358)
• Placing item frames on powder snow (MC-215752)
• Placing item frames on top of the pressure plates / rails / carpets (MC-123221)