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?
self.ensure_one()
        reversed_move = self.copy(default={
            'date': date,
            'journal_id': journal_id.id if journal_id else self.journal_id.id,
            'ref': _('reversal of: ') + self.name})
        for acm_line in reversed_move.line_ids.with_context(check_move_validity=False):
            acm_line.write({
                'debit': acm_line.credit,
                'credit': acm_line.debit,
                'amount_currency': -acm_line.amount_currency
            })
        return reversed_move
    @api.multi
    def reverse_moves(self, date=None, journal_id=None):
        date = date or fields.Date.today()
        reversed_moves = self.env['account.move']
        for ac_move in self:
            reversed_move = ac_move._reverse_move(date=date,
                                                  journal_id=journal_id)
            reversed_moves |= reversed_move
        if reversed_moves:
            reversed_moves._post_validate()
            reversed_moves.post()
            return [x.id for x in reversed_moves]
        return []
    @api.multi
    def open_reconcile_view(self):