summoning an item with custom NBT like

summon minecraft:item ~ ~ ~ {Item:{id:"minecraft:blaze_spawn_egg",Count:1, tag:{display:{Name:"spawn_this"}}}}

won't get detected as item in general anymore if the player moves it in his inventory and then drops it.

@e[type=minecraft:item, limit=1, distance= 5]

won't find the egg anymore. But if the player drops the egg without moving it first, the identifyer will find it.

... I'm using

execute at @e[type=minecraft:item, nbt={Item:{id:"minecraft:blaze_spawn_egg" ,tag:{display:{Name:"spawn_this"}}}}] run summon minecraft:blaze

in minecraft:tick to summon a blaze whenever the egg gets dropped by a mob
which behaves like described above.

... in the current game session even normal items on the ground don't get detected ... I'm not sure what is going on here
summoning the egg and having the blaze spawned automatically still works though

OK, the "distance" filter seems to be buggy. Using it no entity will be detected no matter how high I set its value.
But that is a different bug