Custom fields lose their value if the page contains two forms for the same post type

Symptoms

There is an issue when you have a page with two different Toolset forms set for the same post type.

If one of the forms has a custom field which the other form does not contain, submitting the form without the custom field will remove the custom field value in the other form (the one that does contain that custom field).

Workaround

As a temporary workaround you can use the following steps:

1. Add the custom fields you need to all forms that need to be on the same page.
2. Use CSS to hide the fields in the form where you do not want to display them.