Parameterized URLs work in preview, but not deployed state

[tbunch]

ISSUE:  
Parameterized URLs work in preview mode between data pages, but receive the following error in deployed state.
Error - Cannot display DataPage due to multiple embedded deployments.

CONTEXT: I'm using a series of data pages to search and then redirect to forms to edit objects (normalized many-to-many relationship) following the instructions (https://howto.caspio.com/tech-tips-and-articles/tech-parameters/how-to-create-a-one-to-many-relational-datapage/).  In preview mode - it is working perfectly.

User Steps
1. Account Search - Use search to identify a selection of accounts, on the desired row, click on the `Edit Account` HTML Link (https://[app].caspio.com/dp.asp?AppKey=[app_GUID]&CustodialAccountNumber=[Value])
2. Account Detail Form - The form is called and CustodianAccountNumber passed in the URL.  Error message appears.  Note: I haven't even added any HTML subblocks to add subreports or other deployments into this page.

I have reviewed troubleshooting guidance (https://howto.caspio.com/troubleshooting/why-javascript-is-not-working-with-multiple-datapages-deployed-on-one-page/), and have confirmed both criteria (correct field reference, correct form reference and no duplicate appkeys in the application.)

[tbunch]

SOLVED.

There are some subtile differences based on the deployment method...

FOR the pure URL method 

• the HTML tag  used <a href="https://[app].caspio.com/dp/[appKey]?CustodialAccountNumber=[@field:Institution_accounts_CustodialAccountNumber]">Details Page</a>
• Subforms (tabular reports) followed a similar construction when constructing the src element of the iFrame.

If you are using hosted html (NOT the Caspio HTML pages - I could not get those to accept any parameters), then I recommend the following video: https://www.youtube.com/watch?v=1uPz1cOwNiU