I got a hunch of what it was based on some old forum posts about limits to contact-company associations being set at 10000. I also contacted Hubspot support to see if they could confirm for me.
The v3 API Endpoint has a bug in it where it doesn't properly report the error it should in this case, there is in fact a limit of 10,000 associations for Contacts-Companies, previous versions of the endpoint reported this specific text in the error message, but the v3 endpoint doesn't which led to my intial confusion. I got confirmation as well from Hubspot support that this limit exists.
For reference this is the error text from the v1 endpoint, which should be, but is not, displayed on the v3 endpoint:
{
"status": "error",
"message": "One or more associations are invalid",
I got a hunch of what it was based on some old forum posts about limits to contact-company associations being set at 10000. I also contacted Hubspot support to see if they could confirm for me.
The v3 API Endpoint has a bug in it where it doesn't properly report the error it should in this case, there is in fact a limit of 10,000 associations for Contacts-Companies, previous versions of the endpoint reported this specific text in the error message, but the v3 endpoint doesn't which led to my intial confusion. I got confirmation as well from Hubspot support that this limit exists.
For reference this is the error text from the v1 endpoint, which should be, but is not, displayed on the v3 endpoint:
{
"status": "error",
"message": "One or more associations are invalid",