It's not an answer but try to dump all the scopes - and see if you find it somewhere else. Is it is a "context" scope of a framework? Is it in the arguments scope? Is it in the variables scope? Also look for other structs in those scopes and see of your form is in one of them.

That was an interesting journey. You gave me some good direction to go. My remote function didn't change in that I didn't add any parameters to pass to it. Yet when I dumped the arguments structure into a savecontent block all the form data was in it. I also dumped the form structure and the data was there as well. What was interesting was I could now do local.dID = arguments.debtor_id and it works. That confuses me for sure. Just in that the form scope is present and i can't access the data in a variable assignment, but I could through the arguments scope. Not sure I want to rely on this, but it's a work around for me at least temporarily. Thansk @gavinbaumanis

I can't remember the context - but I know that in our error handler we have code like...

if( isdefined( 'arguments' ) { writeDump( serializeJSON( arguments ) ) }

Because we found certain items in the argument scope that were never expected to be there. Just remembering now... If the error is thrown in a framework library - as opposed to a line of your code - it is entirely feasible that the framework might have your FORM struct in a function's Argument's scope. Now : it is a bit shitty that the framework doesn't handle that properly - to be sure... But the underlying root cause of these issues (for us) - was always the data we were using was faulty... so fixing our data / use of our functions - allowed the framework's code to run without error.