magento 1.9 – After M1->M1 Upgrade – Passwords smaller than 7 characters no longer work and retrieve password fails

Recently upgraded my M1.9.3.6 to M1.9.4.5 to prepare for using php7.3, and all seemed fine but now after a bit of time (and clearly not enough testing before hand by me), I have uncovered some areas that are now causing issues.

It appears passwords that were smaller than 7 characters no longer work, and when trying to use the Forgot password and having the email sent to retrieve your password/reset the password, the error message comes back with;

INVALID METHOD MAGE_CUSTOMER_MODEL_CUSTOMER::CHANGERESETPASSWORDLINKCUSTOMERID(ARRAY ( (0) => B130422155A56F05F432DBD8FB92E839 ) ) 

It appears as if you can enter a password with more characters via the backend and it will save successfully/send the confirmation of password change to the customer however this above issue prevents them from handling this on their own.

Any ideas on the problem/solution? Thanks!