I checked your build logs and I am not sure I fully understand the problem. I do not see you print all environment variables and examine those values. I see however you call Get-AzureSqlDatabaseImportExportStatus in the loop. and output of this command has a lot of places replaced with *****. If this is your concern, then this is expected behavior -- security measure preventing keeping secure variables in clear text.
If your concern is different, then we need more specific information about what specific change broke environment variables and how you examine their values to see if they are broken.