There haven’t been public events since August 2020.
If you publish to https://api.particle.io/v1/devices/events it publishes to all devices claimed to the account whose access token the requester is using.
If you publish to https://api.particle.io/v1/products/:productid/events’ since March 2023, it publishes to all devices in :productid, regardless of claiming, including unclaimed product devices.
Normally when you publish an event (non-product), the access_token owner determines which devices(s) the event will go to based on their claimed account.
What I think is happening is that when you publish to the product event stream, it’s sending to the union of the product and the devices claimed to the access_token.
It should be easy enough to test this by generating an access token for a user other than the account that claimed the devices, which presumably is your account. Using an API user (per product), or a different team member token, would be one way to test this.
Or you could temporarily unclaim the devices and use them as unclaimed product devices and see if that solves the problem.