Hi,
I downloaded your alembic file and have a different behavior between the 2 ways to import it (not the same than you, one is visible, the other not). But when I opened it in Houdini and re export it, now I have the same result.
Be sure when you export your alembic to use Ogawa option (I didn't find it in Blender).
After investigating a little bit more, the geo inside your alembic are greyed in the reference. I have to override the visibility to make them visible. Be sure in Blender to have them visible or maybe you have different state of your simulation (like proxy) and it's what you currenlty exporting ?
Check also this options :

Cheers