Well for giggles went and looked at my Alliant interface for reason codes and found this. My 60D late was from April 2018, these are March and June reason codes from 2019. Looks like a separate scorecard too if the reason codes behave similarly to FICO ones. This is on a closed account.
This is also a departure from FICO which appears to be recent until 2 years on FICO 04/8/9 at least.
March 2019:
1. You have too many delinquent or derogatory accounts
2. The worst payment status on your accounts is delinquent or derogatory
3. Lack of sufficient credit history on bankcard or revolving accounts
4. Open real estate acct balances are too high compared to their loan amts
June 2019
1. You have too many delinquent or derogatory accounts
2. Lack of sufficient credit history on bankcard or revolving accounts
3. The date that you opened your oldest account is too recent
4. Open real estate acct balances are too high compared to their loan amts
