Notice: Undefined index: opencalais_calaisdocumentc_tags in locale_field_entity_form_submit() (line 438 of /var/www/html/drupal7/modules/locale/locale.module).

Have a look here,
https://www.drupal.org/node/2556131
this resolved the undefined index issue in multilingual sites but since v1.2 this is not enough

Finally, I don't think this issue is related to translations on multilingual sites but rather to the "Collect Tags into Vertical Tab" option in opencalais parameters (admin/config/content/opencalais/settings) which makes a fieldset to contain all opencalais fields but then opencalais fields are not at top level of $form array but inside a $form['opencalais'] key.
See it here in opencalais_form_node_form_alter:

      foreach ($fields as $field_name) {
        $form['opencalais'][$field_name] = $form[$field_name];
        unset($form[$field_name]);
      }

Core locale module is not aware of this change and, because it is based on the bundles structure to test the form's values, it still looks at $form[$field_name] instead of $form['opencalais'][$field_name] which causes the error. See it here: (locale_field_entity_form_submit, lines 435-438)

    foreach (field_info_instances($entity_type, $bundle) as $instance) {
      $field_name = $instance['field_name'];
      $field = field_info_field($field_name);
      $previous_language = $form[$field_name]['#language'];

This is valid even in v1.2, don't care about what I wrote in my previous message :)
Conclusion: don't use Vertical Tab until an other coding is available

I see, I had CKEditor disappearing also. I think you'll have to follow the other subject I suggested on my first reply #2. Also, my first post on the issue at https://www.drupal.org/node/2405269 may be useful to understand why CKEditor toolbar doesn't appear any more while editing a node. Of course, don't hack original files, back up them and make any changes in a copy of your files. Unfortunately I don't have the needed time to learn making patches (my progress is very slow on that), and I can only propose dirty solutions with no guarantee.

This looks like it might be some kind of Javascript issue. I am looking into it this morning.

See if this patch addresses this specific issue, not the CKEditor/JS one which should be a separate issue

The CKEditor issue should be handled in

https://www.drupal.org/node/2405269

This patch is not on the main repository on github. Once passed, will move it here.

https://bitbucket.org/mrbagnall/opencalais

now in dev branch - Messed up the attribution

It works ! with 7.x-1.3+3-dev (2016-Aug-31), both with vertical tabs or not. Tested on two sites, one simple + one very complex. No more problem with CKEditor. Also opencalais_cron is running each time cron (Elysia cron) is running (perhaps we should open a feature request ticket for improving the admin/config/content/opencalais/bulk report with nb_proccessed/total_nb_to_be_proccessed)