It seems that it would otherwise silently skip the rescan for pre-backup used keys that are still waiting to be generated into the keypool?

See also #11249 
#include <chain.h>
#include <clientversion.h>
#include <core_io.h>
#include <fs.h>
#include <hash.h>
#include <interfaces/chain.h>
#include <key_io.h>
#include <merkleblock.h>
#include <rpc/util.h>
#include <script/descriptor.h>
#include <script/script.h>
#include <script/standard.h>
#include <sync.h>
#include <uint256.h>
#include <util/bip32.h>
#include <util/time.h>
#include <util/translation.h>
#include <wallet/rpc/util.h>
#include <wallet/wallet.h>
#include <cstdint>
#include <fstream>
#include <tuple>
#include <string>
#include <univalue.h>
using interfaces::FoundBlock;
 {
std::string static EncodeDumpString(const std::string &str) {