Email messages not being sent from default account
I have 2 apple email accounts: the one associated with my main apple account and a 2nd that I use for family/friend/acquaintance emails only. This 2nd account is the email account I have chosen to be the default mail account on all my devices-iMac, iPad, iPhone. When I send an email from iMac or iPhone, that 2nd email is 'who' the email is from, however, the last few I've sent from my iPad shows the email being sent from my main account, even those the settings on the iPad says my default account is indeed my 2nd account. Why would this happen?
iPad Pro 12.9-inch, 2nd Gen, Wi-Fi