Multiple duplicate activities generated for scope change

[TheTechromancer]

  Full diff:
    [
        'Host t1.tech.evilcorp.com became in-scope for target evilcorp1 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp1 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp1 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp1 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp2 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp2 due to '
  +     'in-target host SELF->t1.tech.evilcorp.com',
  +     'Host t1.tech.evilcorp.com became in-scope for target evilcorp2 due to '
        'in-target host SELF->t1.tech.evilcorp.com',
        'Host t1.tech.evilcorp.com became in-scope for target evilcorp2 due to '
        'in-target host SELF->t1.tech.evilcorp.com',
        'Host t2.tech.evilcorp.com became in-scope for target evilcorp1 due to '
        'in-target host SELF->t2.tech.evilcorp.com',
        'Host t2.tech.evilcorp.com became in-scope for target evilcorp2 due to '
        'in-target host SELF->t2.tech.evilcorp.com',
        'New asset: [t1.tech.evilcorp.com]',
        'New asset: [t2.tech.evilcorp.com]',
        'New open port: [t1.tech.evilcorp.com:443]',
        'New open port: [t1.tech.evilcorp.com:80]',
        'New open port: [t2.tech.evilcorp.com:443]',
        'New technology discovered on t1.tech.evilcorp.com: '
        '[cpe:/a:apache:http_server:2.4.12]',
        'New technology discovered on t2.tech.evilcorp.com: '
        '[cpe:/a:apache:http_server:2.4.12]',
        'New technology discovered on t2.tech.evilcorp.com: '
        '[cpe:/a:microsoft:internet_information_services]',
    ]

[TheTechromancer]

This seems to be a race condition, since it only happens sometimes. We are never running more than one handle_event() at once, and we're making sure to use strict_collection when updating an asset:

    async def update_asset(self, asset: Asset):
        asset.modified = utc_now()
        await self.strict_collection.update_one({"host": asset.host}, {"$set": asset.model_dump()}, upsert=True)

Unsure how this is happening.