Unable to save customised transform - error 259, when making specific change

I'm creating an MST for Adobe Acrobat Reader DC. So far the process has been fine, however there is a particular option where when I change it, the package cant be saved.

The option I want to toggle is:

Online Services and features > When launching PDF in internet explorer, prompt user with open/save dialogue.

If i toggle this off, as i want to I get the following error:

Unable to submit changes, MSI Set Value failed, Error Code = 259

I've tried with different downloads of Adobe Acrobat Reader, I have tried editing the msi both locally and remotely. What is causing this?