Monsters spawned by a Trial Spawner placed by a player rarely have any equipment

The Trial Spawners manually placed in Creative Mode, which trigger Ominous trial, rarely spawn zombies with armor and weapons, and skeletons (with other variant) do not spawn with armor, even on Hard difficulty. However, zombies and skeletons (with other variant) spawned by naturally generated Trial Spawners in the Trial Chambers are equipped with armor and weapons as expected. After checking the wiki and update notes, I believe this is a bug where the game content does not match the description. Please fix this issue, thanks!

I am a map creator, and I want to add Trial Spawners as challenges in some levels while manually creating a PvP map. This issue makes the challenges lack difficulty. If it is a special setting where only Trial Spawners naturally generated in the Trial Chambers can spawn monsters with equipment, please let me know.