Would you tell us which app you use? Acrobat DC for iOS or Android?
Is it the file stored locally on your device or in the cloud (e.g. Adobe Document Cloud, Dropbox, Google Drive)?
Is it possible that you opened the filled PDF form in Apple Mail or other non-Acrobat app?
I have the ZTE Z970 (Android). They are saved on my phone I will try to
have them uploaded on my Dropbox and try again thank you