Discord.net weird Bug

IUserMessage messageGet = await messageIn.GetOrDownloadAsync();
IMessageChannel channelGet = await channelIn.GetOrDownloadAsync();

ulong messageUserId = messageGet.Author.Id;

//This call always seems to come back null if user is offline. Not sure if this is intended or not.
var messageUser = await channelGet.GetUserAsync(messageUserId, CacheMode.AllowDownload) as SocketGuildUser;