And yet LE is to blame - LOL
The three RFCs you mention fail to show how LE is in any kind of violation:
RFC 1912 "Common DNS Operational and Configuration Errors"
This memo does not specify an Internet standard of any kind.
RFC 2308 "Negative Caching of DNS Queries (DNS NCACHE)"
Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol.
RFC 4035 "Protocol Modifications for the DNS Security Extensions"
Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol.