I found a 7 year old bitcoin wallet that i had on Bitcoin core, i put a small amount in there approx $40, now worth over £136.

I found the root key that i used to recover the wallet, i downloaded the whole blockchain that took several days only to see a 0 bal at the end.

I then extracted the BIP39 that i imported into electrum, again which showed 0 bal, but also showed movement of the funds not long after i setup the wallet.

The funds are still in this other wallet (link), so they were never stolen.

Just wondering how this could have happened assuming the funds were not stolen, could i have made a mistake at the time & not completely downloaded bitcoin core causing the funds to slip to another address?

Would i have had multiple wallet addresses in my bitcoin core address that i should be still able to access?

https://www.blockchain.com/explorer/addresses/btc/1Cvoe4whXCKB7hL9KJEZHvT22Hdiitz26H