What can I do ...
Re-import the addresses
to recover the funds?
Imported addresses are called "watch-only" or "unspendable" addresses.
If you ever had control over the money at these imported addresses you would have had a private-key somewhere for them.
To give your current wallet control over that money (the ability to spend it) - you must either "import" the private key(s) or "sweep" those private keys into your wallet.
Sweeping private keys is usually considered safer than importing private keys for the reasons demonstrated by your question - imported things are not recovered by using a recovery phrase to recreate the wallet.
The recovery phrase only recovers private-keys and addresses that were generated by the original wallet, not things that were imported into it.
If you don't know the private keys for the imported addresses, there are a couple of possibilities depending on where you got those addresses from in the first place:
- You have another wallet that contains those keys
- Someone tricked you and you never had any Bitcoin money at those watch-only addresses.
Confusion about the nature of imported addresses is something we often see in victims of fraud.