it looks like you are using a multisig wallet. Since you do not seem to be aware of that, I suppose it is a wallet with two-factor authentication. Maybe you saved the local transaction without broadcasting it?

Hello, yes, about having multisig wallet I already know from other forum, before wasn't aware about that. Here just wanted to write about a bug/error. Like I wrote:
"In the "Send" tab next to the transaction there is the info "unconfirmed". Someone on bitcointalk.org gave me an advice to report that thing here so I am doing that."
And the advice the person gave me, sharing that reason: "That is unintended"

@ecdsa I guess OP's point is that the invoice/request gets into the PR_UNCONFIRMED state from either a mempool tx or a local tx, and if it happens for a local tx, then that is potentially confusing for the user. We could potentially split PR_UNCONFIRMED into two states to be able to distinguish these.

From IRC:

<s7r> [...] this also breaks electrum in merchant mode?
<s7r> e.g. I send to an electrum merchant a tx, and cancel it (RBF double spend) from my electrum client. In the merchant it will remain as Unconfirmed (Local) forever.
<s7r> we need to split PR_UNCONFIRMED in complete | partially_signed | local
<s7r> and a way to automatically remove / expire payment requests that have a LOCAL transaction for more than N seconds, something like this
<s7r> oh, or mempool TX or local TX maybe, since mempool will not accept a TX if not completely signed. as well as if its parent UTXO is spent in a RBF double-spend.