This is Experimental (Theoretically It Should Be) I Have Not Tried It Myself Add It to Your Server in a Controlled Way I Do Not Accept Responsibility

We can perhaps fix the error by overriding the data in l10n_cl_edi.models.account_move

ir.ui.view patch 

<record id="override_l10n_cl_no_percent" model="ir.ui.view">
  <field name="name">l10n_cl_edi.no_percent_override</field>
  <field name="model">account.move</field>
  <field name="inherit_id" ref="l10n_cl_edi.template_id_goes_here"/> 
  <field name="arch" type="xml">
    <xpath expr="//t[contains(.,'%')]" position="replace">
      <t t-esc="(tax.amount * 100)|format('%.2f')"/>
    </xpath>
  </field>
</record>

How To add this override

create special module 

basic doc struct

custom_l10n_cl_no_percent/

├── __init__.py

├── __manifest__.py

└── views/

    └── no_percent_override_view.xml

manifest.py

{
    'name': 'CL EDI percent Override',
    'version': '16.0.1.0.0',
    'category': 'Localization/Chile',
    'summary': 'Remove % from tax rate in Chile edi xml',
    'depends': ['l10n_cl_edi'],
    'data': [
        'views/no_percent_override_view.xml',
    ],
    'installable': True,
    'auto_install': False,
}

views/override.xml

<odoo>
  <data>
    <record id="override_l10n_cl_no_percent" model="ir.ui.view">
      <field name="name">l10n_cl_edi.no_percent_override</field>
      <field name="model">account.move</field>
      <field name="inherit_id" ref="l10n_cl_edi.view_l10n_cl_edi_traslado_template"/>
      <field name="arch" type="xml">
        <xpath expr="//t[contains(.,'%')]" position="replace">
          <t t-esc="(tax.amount * 100)|format('%.2f')"/>
        </xpath>
      </field>
    </record>
  </data>
</odoo>

inherit_id: Qweb external id 

how to find external id in server terminal  

grep -R "TasaOCuota" addons/l10n_cl_edi

This is Experimental (Theoretically It Should Be) I Have Not Tried It Myself Add It to Your Server in a Controlled Way I Do Not Accept Responsibility