RE: Campaign linked to a form not always added to lead who summitted the form
Hi,
You are using a lower version of marketing, in my test environment the marketing form does not have the campaign field.
I recommend that you create a workflow, please refer to my steps.
Go to advanced setting>process>new process>create workflow

Create the following workflow, you can also modify the criteria, for example to update the lead only if the topic contains the name of the submitted form. The condition I use here is that if the newly created lead has a value for lead source, it will be associated with the specified campaign.


Remember active your workflow.

Now it works well.

By the way, you mentioned sometimes it is and some times it is not.
I think the reason is that the form submission may have created a lead with the same email address, causing the lead to not be added.