Error on attempt to build a Drupal 8.9.20 instance

Second attempt today, produces same result: https://simplytest.me/tugboat/progress/66195cb9d5dd4604b762fa5d/66195cb9...

Error:

This may be the error:

Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. It is recommended that you run `composer update` or `composer update <package name>`.
- Required package "zaporylie/composer-drupal-optimizations" is not present in the lock file.
This usually happens when composer files are incorrectly merged or the composer.json file is manually edited.
Read more about correctly resolving merge conflicts https://getcomposer.org/doc/articles/resolving-merge-conflicts.md
and prefer using the "require" command over editing the composer.json file directly https://getcomposer.org/doc/03-cli.md#require-r

Console output just prior to this error:

HEAD is now at e187f925ed Drupal 8.9.20
66195cb9d5dd4604b762faed# /bin/sh -c echo "SIMPLYEST_STAGE_DOWNLOAD"
SIMPLYEST_STAGE_DOWNLOAD
66195cb9d5dd4604b762faed# /bin/sh -c cd "${DOCROOT}" && composer require zaporylie/composer-drupal-optimizations:^1.0 --no-update
./composer.json has been updated
66195cb9d5dd4604b762faed# /bin/sh -c cd "${DOCROOT}" && composer install --no-ansi
> Drupal\Composer\Composer::ensureComposerVersion
Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. It is recommended that you run `composer update` or `composer update <package name>`.