Impacted versions:
At least version 10, version 11(Can only re-produce the problem sometimes)

Steps to reproduce:
Please see this screencast recorded on odoo runbot.
https://youtu.be/cSPQvp9jQJc

Current behavior:
When users search by account in Journal Entries List View. A special value "dummy_account_id" is set in context, in order to facilitate search by account on account.move level.
With this context value , when users create a journal entries, the system will add default value before the creation.

https://github.com/odoo/odoo/blob/fc69b37cf710623ea215cd085e998679d8c50985/odoo/models.py#L3802

This method will set "dummy_account_id" to the previously searched account in vals.

Then the system continue creating account.move and related account.move.line records.
It is fine until the system run this:
https://github.com/odoo/odoo/blob/fc69b37cf710623ea215cd085e998679d8c50985/odoo/models.py#L3830

Since "dummy_account_id" is related field, and it now has value. The system will change the first related  account.move.line record to dummy_account_id.

Eventualy, the account is wrongly set to "dummy_account_id".

Expected behavior:
This is a feature which will fill the form field value with searched value for users. But the journal entry creation should not be affected by dummy_account_id, since it is only for searching purpose.

@Yenthe666 Would you please review this issue and help to bring related odoo staff to this issue?
# Em
        # Th
        if not self:
            return True
        #Per
        company_ids = set()
        all_accounts = []
        partners = set()
        for line in self:
            company_ids.add(line.company_id.id)
            all_accounts.append(line.account_id)
            if (line.account_id.internal_type in ('receivable', 'payable')):
                partners.add(line.partner_id.id)
            if line.reconciled:
                raise UserError(_('You are trying to reconcile some entries that are already reconciled!'))
        if len(company_ids) > 1:
            raise UserError(_('To reconcile the entries company should be the same for all entries!'))
        if len(set(all_accounts)) > 1:
            raise UserError(_('Entries are not of the same account!'))
        if not all_accounts[0].reconcile:
            raise UserError(_('The account %s (%s) is not marked as reconciliable !') % (all_accounts[0].name, all_accounts[0].code))
        if len(partners) > 1:
            raise UserError(_('The partner has to be the same on all lines for receivable and payable accounts!'))
        #rec