Technical question: recovering two NEAR implicit accounts from one Sender seed phrase

Hello NEAR Developer Relations / NEAR developers,

I am trying to recover an old NEAR account that I previously used with Sender Wallet.

I have two NEAR implicit accounts involved in the same REF/RHEA transaction history:

• Account A: 9b6495b94edd6ae1f2e31f3a31a20475a5288aa66f666e7a4794b0b9e5571968 (ending …1968)
• Account B: fdaa5bffa99c154cdd664d7352c6ae3b06a4c4516fcfd3e7c13fd1580b4068bf (ending …68bf)

I still have the original 12-word seed phrase that I used with Sender Wallet.

When I import/recover this seed phrase today, I can access Account A (…1968), but I cannot recover or access Account B (…68bf) using the same seed phrase.

The …68bf account is still active on-chain and contains my RHEA assets.

RHEA support recently reviewed the on-chain transaction sequence and stated that the …68bf account was created by a 0.1856 NEAR transfer, and that the relevant transaction sequence was signed by my own keys.

My main technical question is:

Can one 12-word seed phrase generate or derive multiple NEAR Ed25519 key pairs, and therefore multiple implicit NEAR account IDs, by using different derivation paths or account/key indexes?

If yes:

1. What derivation-path/index scheme was historically used by NEAR-compatible wallets such as Sender Wallet around July 2025?
2. Could the same seed phrase therefore produce different NEAR implicit accounts depending on the derivation path or index?
3. Is there an official NEAR method or tool that allows a user to determine which public keys / implicit accounts can be derived from a seed phrase, without exposing the seed phrase?

I am not asking anyone to handle or receive my seed phrase or private keys. I only want to understand the technical relationship between the seed phrase, derivation path/index, public key, and the two implicit account IDs.

For reference, one relevant transaction is:

dHZtaUpkCXSyUCQKVp3JjTXc7x1eoBSvrNWQDzxV8Hp

This is the transaction in which approximately 0.1856 NEAR was transferred to …68bf, which RHEA identified as the transaction creating that implicit account.

I would greatly appreciate guidance from the NEAR developers on how I can technically verify whether …68bf could have been derived from my original Sender seed phrase through a different derivation path or index.

Thanks!

The specific facts of the matter are as follows:

I previously held REF tokens associated with the Near DEX. Around June/July 2025, the developers announced a merger with RHEA and a scheduled token conversion from REF to RHEA, running from late 2025 through early 2026. I used a single Sender Wallet for the REF/RHEA conversion. I carefully wrote down and stored the 12-word Seed Recovery Phrase (SRP). I am currently trying to recover that wallet/account using the saved seed phrase, but I am encountering two different implied NEAR accounts.

Throughout the first quarter of 2026, I regularly used that same SRP (from the REF/RHEA conversion) to log into my Sender Wallet and check my tokens; on February 25, 2026, I even accessed the wallet to transfer NEAR to another address. However, two weeks ago, when I used my SRP to recover the wallet in Sender or Weteor, it displayed an address ending in …1968 instead of the address ending in …68bf that I had been using. Consequently, I am unable to withdraw the RHEA and NEAR held in the …68bf wallet.

The two accounts are:

9b6495b94edd6ae1f2e31f3a31a20475a5288aa66f666e7a4794b0b9e5571968 This is the Sender Wallet address for depositing REF. I used this address to receive and send REF. 2. fdaa5bffa99c154cdd664d7352c6ae3b06a4c4516fcfd3e7c13fd1580b4068bf — This is the account resulting from the REF-to-RHEA claim, executed within my single Sender wallet. I subsequently held the RHEA here and considered this my primary RHEA account; the RHEA balance remains stored at this address on the blockchain. The sequence of events was as follows: On July 25, 2025, I transferred REF from the MEXC exchange to my Sender Web3 wallet; the wallet address used for the REF transfer ended in “…1968”. On that same day, I deposited 0.2 NEAR for gas fees at 16:17:09; the receiving address ended in “…1968”. At 16:26:04, a transaction automatically moved 0.185 NEAR from the “…1968” wallet to the “…68bf” wallet. A few hours later, I deposited more REF into the “…1968” wallet. Then, at 23:01:29, I deposited another 11.8 NEAR, and the receiving address was “…68bf”. Immediately afterward, at 00:25:15 on July 26, 2025, the protocol automatically transferred 3 NEAR from the “…68bf” wallet to the “…1968” wallet. At 00:26:36 on July 26, 2025, an automated network transaction deposited 0.0001 NEAR from wallet …1968 to wallet …68bf. At 00:26:59 on July 26, 2026, an automated transaction occurred transferring funds from wallet …1969 to the wallet token.v2ref-finance.near; following this, wallet …1968 ceased all transaction activity while retaining a balance of 2.7… NEAR. After wallet …1968 stopped transacting, wallet …68bf automatically converted the claimed REF to RHea. By 10:19:38 on October 9, 2025, all REF had been converted, and I manually claimed the RHea. Since then, I have held the assets and occasionally checked the wallet to ensure the RHea balance remained intact. I also subsequently withdrew NEAR from wallet …68bf to another wallet.

I need your assistance in locating the wallet address ending in …68bf—where I claimed REF/RHea and have stored RHea from October 9, 2025, to the present—to confirm it still exists on the blockchain. Thank you!