If an ominous vault is created using a debug stick, it will only accept regular trial keys and will completely reject ominous trial keys.
Steps to reproduce:

• create a new world in creative mode
• grab a trial vault out of the creative inventory
• place down the trial vault
• use /give @s debug_stick
• use the trial key on the trial vault to turn it into an ominous trial vault
• attempt to use an ominous trial key on the trial vault
• it doesn’t work
• use a regular trial key on the ominous vault
• it works