Description
With a drupal-site, that has translations enabled and e.g. search_api or bef-module installed executing drush cim will cause the system to throw an exception in TranslatableMarkup Line133 and depending on core-version, loop infinitely or fail although the configuration itself was properly imported.
Rerunning drush cim will then finish without a problem, as all the configurations have been imported and the translations that were missed are not recreated
This problem is neither compatible with with a CD-approach nor does it inspire confidence.
Reason
The problem arises because LocalConfigManager:178 checks that the value is neither an empty string nor null, but it does not check if it is a string at all.
BEF-configuration in yaml:
....
bef_slider_step: !!float 1
....
Fix
The following patch will test that the value is a string and not empty.