Same thing in our apps:
SIGABRT: Application tried to present modally a view controller <_SFAppAutoFillPasswordViewController: 0x10d006c20> that is already being presented by <UIKeyboardHiddenViewController_Autofill: 0x10d006fc0>
Also we got another possibly related crash: SIGABRT: Application tried to present modally a view controller <_SFExternalPasswordCredentialViewController: 0x111f062c0> that is already being presented by <UIKeyboardHiddenViewController_ExternalCredential: 0x10ff6c5b0>
Probaply the crash reason is the same, I guess the difference is whether a password is stored in keychain already or not