Search redirect block - wrong redirect when two blocks are present on the same page

Problem/Motivation

When page contains two instances of search_redirect_block it can lead to missmatch in redirects.

Steps to reproduce

1. Place one search_redirect_block block in header and set redirect_path option to /search
2. Create an overview page with another search redirect block in sidebar, and set redirect_path option to <current>
3. Go to overview page, submit form in header - see that it reloads current overview page instead of redirecting to /search

Proposed resolution

This seems to be related to core issue.
Following this issue I've created a simple form alteration:

/**
 * Implements hook_form_FORM_ID_alter().
 */
function mymodule_form_search_api_fulltext_facet_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  $form_state->setRequestMethod('POST');
  $form_state->setCached(TRUE);
}

and it solved the problem.

Remaining tasks

Needs triage, decide if proposed "workaround" can be used.

User interface changes

None.

API changes

None.

Data model changes

None.