diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index c4bf86a40bd2..b05c9a08d379 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -609,6 +609,11 @@ func NewBlockChainAPI(b Backend) *BlockChainAPI {
 }
 
 // ChainId is the EIP-155 replay-protection chain id for the current Ethereum chain config.
+//
+// Note, this method does not conform to EIP-695 because the configured chain ID is always
+// returned, regardless of the current head block. We used to return an error when the chain
+// wasn't synced up to a block where EIP-155 is enabled, but this behavior caused issues
+// in CL clients.
 func (api *BlockChainAPI) ChainId() *hexutil.Big {
 	return (*hexutil.Big)(api.b.ChainConfig().ChainID)
 }