user102915: I use Bitcoin Core to create SegWit paper wallets for friends and family.
After creating the wallet via the GUI, the steps I take are as follows:

getnewaddress  # Carry this public key back to the paper wallet
dumpprivkey *step-1-key*  # Carry this private key back
to the paper wallet

Then, using qrencode, I also print the two related QR codes.
I tried to verify the correctness of the steps, importing one of the wallets I created into Bitcoin Core, as follows:
(Make Blank Wallet > Yes)

importprivkey *step-2-key*

After waiting a while, it opens it correctly, but I see "HD key generation is disabled" (whereas at the time of creation it was enable).
Why does this happen? What am I doing wrong?

UPDATE
[sic the text below was posted as an answer, and I believe it was intended as a follow-up addition to the OP question.  I am copying it here to better position the question]
Before opening the thread, I had already tried to import a wallet on Bitcoin Core using the Master Private Key previously extrapolated with dumpwallet. In summary I had done:
getnewaddress
dumpprivkey *step_1_key*
dumpwallet

Then trying to import the newly created wallet again:
Make Blank Wallet > Yes
importprivkey *Master_Private_Key_(from_"dumpwallet")*

However, when I tried to issue the last command, I got the following error message: Invalid private key encoding (code -5)
Furthermore, I have now understood that the wallets I want to create for friends and relatives must be protected by a password (therefore BIP38 Encrypt) so that, by changing it, they have the security that I no longer have any access to their wallets. Is it therefore possible to create, through Bitcoin Core (it is the only software I trust), to create a SegWit wallet that has both HD seed and BIP38 technology? If so, what data should I print on the wallet, knowing that I want to provide these people with both the public and private keys (in this case, however, protected by a password)?
If you could help me I would be grateful: I'm going crazy!

user26873: The steps you described is for a single private key, not a BIP32 wallet. If you are looking to back-up your HD seed (master key) in bitcoin-core you should use the dumpwallet command.
https://bitcoincore.org/en/doc/0.18.0/rpc/wallet/dumpwallet/

102915: <p>I use Bitcoin Core to create SegWit paper wallets for friends and family.
After creating the wallet via the GUI, the steps I take are as follows:</p>
<ol>
<li><code>getnewaddress</code>  # Carry this public key back to the paper wallet</li>
<li><code>dumpprivkey *step-1-key*</code>  # Carry this private key back
to the paper wallet</li>
</ol>
<p>Then, using <code>qrencode</code>, I also print the two related QR codes.
I tried to verify the correctness of the steps, importing one of the wallets I created into Bitcoin Core, as follows:
(Make Blank Wallet &gt; Yes)</p>
<ul>
<li><code>importprivkey *step-2-key*</code></li>
</ul>
<p>After waiting a while, it opens it correctly, but I see &quot;<em>HD key generation is <strong>disabled</strong></em>&quot; (whereas at the time of creation it was enable).
Why does this happen? What am I doing wrong?</p>
<hr />
<p><strong>UPDATE</strong></p>
<p><em>[sic the text below was posted as an answer, and I believe it was intended as a follow-up addition to the OP question.  I am copying it here to better position the question]</em></p>
<p>Before opening the thread, I had already tried to import a wallet on Bitcoin Core using the Master Private Key previously extrapolated with dumpwallet. In summary I had done:</p>
<pre><code>getnewaddress
dumpprivkey *step_1_key*
dumpwallet
</code></pre>
<p>Then trying to import the newly created wallet again:</p>
<pre><code>Make Blank Wallet &gt; Yes
importprivkey *Master_Private_Key_(from_&quot;dumpwallet&quot;)*
</code></pre>
<p>However, when I tried to issue the last command, I got the following error message: Invalid private key encoding (code -5)</p>
<p>Furthermore, I have now understood that the wallets I want to create for friends and relatives must be protected by a password (therefore BIP38 Encrypt) so that, by changing it, they have the security that I no longer have any access to their wallets. Is it therefore possible to create, through Bitcoin Core (it is the only software I trust), to create a SegWit wallet that has both HD seed and BIP38 technology? If so, what data should I print on the wallet, knowing that I want to provide these people with both the public and private keys (in this case, however, protected by a password)?</p>
<p>If you could help me I would be grateful: I'm going crazy!</p>
 26873: <p>The steps you described is for a single private key, not a BIP32 wallet. If you are looking to back-up your HD seed (master key) in bitcoin-core you should use the <code>dumpwallet</code> command.</p>
<p><a href="https://bitcoincore.org/en/doc/0.18.0/rpc/wallet/dumpwallet/" rel="nofollow noreferrer">https://bitcoincore.org/en/doc/0.18.0/rpc/wallet/dumpwallet/</a></p>
