Password-based SSO not passing credentials correctly

Question

Hey folks,

SSO setup for a number of apps (sites) we provide to our users via the My Apps portal. The majority of the apps work well, either sign-in with the assigned credentials, or at the very least pass the creds to the user/pass fields and wait for the login button to be clicked.

However, we have some apps that just refuse to send the credentials from the Azure groups assignment, into the fields. We also have others which pass the password to the username field.

We've done both automatic and/or manual detection on the fields successfully, and been able to assign the users/groups and assign the credentials on behalf of successfully.

We are running the My Apps Secure Sign-In Extension, version 8.2.1.196 (uninstalling and reinstalling in both Chrome and Edge to eliminate the extension being the cause) and we've followed the MS documentation to try the detection methods again, do the Dev Tools piece from the Console - window.location=<sign-in url>, and everything else inbetween. I have HAR files of both working apps and apps that are behaving badly, but to be honest, I don't know what I'm looking for to see what is (or isn't) happening.

Are we at the point where the site might not be configured to work with password-based SSO? I mean, they worked when we used them in Okta prior to migrating to Azure. Or is it a case of reaching out to the site owners and getting them to work with MS to resolve?

Basically, I'm asking is there anything else we can do, to resolve on our side before saying it's up to the vendor and MS to resolve.

Thanks.