latest version of WP core is breaking my shortcodes inside form fields

Hello,

I had a plugin made that allowed me to easily merge a contact's info onto my wordpress pages. We use short codes to merge customer data onto the page which is typically pulled from a URL string.

Here is an example:

http://magickidsparty.com/merge-test-form/?Name=Bob&Email1=new@abc.com

This merges in the contact's name anywhere I use the short code on my WordPress page: [as what="Name"]

This used to also work in form fields so I could pre-fill customer info they had already given me previously. Ever since the 4.2.3 update, the merge codes no longer work as the preset value in the form fields.

Here is a screenshot of what it looks like now:

http://screencast.com/t/Rb5eMQv3BNp

As you can see, instead of filling in the customer's name, it is showing part of the merge code itself.

In the form code, my value looks like this: value="[as what="Name"]"

Here is a copy of the WordPress plug-in I had made:

https://www.sugarsync.com/pf/D646892_84631739_9998729

Unfortunately, the gentleman who made the plug-in for me has disappeared otherwise I would ask for his help. Anyone have any idea why this latest version of WordPress will allow my merge codes to work inside of the form fields?

I did downgrade my WordPress 4.2.2, and my short codes that merge in the customer data work just fine in the form fields. This obviously tells me it has something to do with this latest core WP update.

I would rather not have to roll back all of my WordPress installations. I did see in the list of changes for 4.2.3 this: "Shortcodes: Improve the reliablity of shortcodes inside HTML tags. Merge …"

Any help would be greatly appreciated. Thanks so much!

David