Hellhole Rats effect is not triggered by Rat Swarm support tokens [investigating]

biosterous

Cards effected:

• Hellhole Rats (Creature - Rat), Masterpiece, Wilds of Eldraine
  Effect: When a Rat enters the battlefield under your control, [opponent discards card(s) and takes damage based on various factors]

• Rat Swarm (Support Card - Rat Enchantment)

Expected behaviour:
1. Have Hellhole Rats on the battlefield
2. Do any action that creates a Rat Swarm Support under your control
3. Hellhole Rats effect triggers, opponent discards and takes damage

Actual behaviour:
1. Have Hellhole Rats on the battlefield
2. Do any action that creates a Rat Swarm Support under your control
3. Hellhole Rats does not trigger

Observed behaviour with using Creature cards with the Rat subtype:
1. Have Hellhole Rats on the battlefield
2. Cast a creature with the Rat subtype
3. Hellhole Rats effect triggers correctly, opponent discards and takes damage

Hellhole Rats needs to be fixed so that it triggers off of Rat Swarm tokens entering the battlefield (as the card says should happen).