@SanfordWhiteman : Im trying to figure out if this issue is device or browser specific. Is there a way I can know the exact browser and the device a lead used to visit the landing page.
I see 'User Agent' string {Mozilla/5.0 (Linux; Android 8.1.0; Infinix X5515 Build/O11019) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.126 Mobile Safari/537.36} in the filled out form activity but it is not giving the exact browser or device info.
That's Chrome 66 on Android 8 (so both browser and OS versions are quite old).
You can do lookups here: https://developers.whatismybrowser.com/useragents/parse/#parse-useragent
This might not be the issue, but in the past we had found lots of Facebook paid ad spend coming through as referrals simply as "m.facebook.com" and similar - they didn't preserve the URL parameters.
Here is some further reading: https://holini.com/m-lm-l-facebook-com-referrals/