3 official rulings from Bandai, last ruled Mar 28, 2024. Straight answers to how this card actually resolves.

I attack with this Digimon when my opponent has no Digimon in play with no digivolution cards. I use this card's <When Attacking> effect to trash the digivolution cards of an opponent's Digimon. If this results in my opponent having a Digimon card with no digivolution cards in play, can I activate <Jamming> on the same attack?
Yes. If this card's <When Attacking> effect results in an opponent's Digimon having no digivolution cards, this card gains <Jamming>.
Ruled Mar 28, 2024
My opponent has this Digimon in play. I attack my opponent with a Digimon that has <Security Attack +1>, and flip over [BT1-101]/[Howling Crusher] from their security stack. If its <Security> effect results in the attacking Digimon having no digivolution cards, does the attack end immediately?
No. You've already declared the attack, so even if your attacking Digimon loses its digivolution card, [Hexeblaumon]'s effect doesn't end the attack midway.
Ruled Mar 28, 2024
I attack my opponent with this Digimon, which has <Security Attack +1>, and flip over a Digimon card with a <Security> effect during the first security check. If this results in a Digimon with no digivolution cards entering my opponent's battle area, does this Digimon gain <Jamming> starting with the next security check?
No. This card's <When Attacking> effect has already finished resolving. Even if a Digimon with no digivolution cards enters play afterwards, this card doesn't gain <Jamming>.
Ruled Mar 28, 2024
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Questions and answers are Bandai's official rulings, collected and translated by the DigimonCardGame Wiki community and reused here under CC BY-SA. Card names and card text are © their respective publishers; Combalo is not affiliated with Bandai.