Is "inherited" replace-by-fee signaling implemented as described in BIP125?
The answer to this question is: no, inherited signaling is not currently implemented in Bitcoin Core as described in BIP 125.
In May 2021, Antoine Riard discovered the missing implementation could be exploited in the context of the Lightning Network &quot;pinning attacks against second-stage HTLCs&quot; as well as other contexts:
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-May/018893.html