TypeError: Drupal\swiper_formatter\Plugin\views\style\SwiperFormatterStyle::getEntity()

Thanks for reporting and providing an MR for this issue.
We'll review and get back to you if needed.

I just ran into one more spot where the row's entity can live and have added a check for it in MR 21: $row['entity']['#' . $row['entity']['#theme']].

Thank you @chrisolof for your contribution, the changes look great!
The provided solution is a great improvement by sticking to the expected return type and adding a fallback foreach at the end.
I tested this with the ECK → module and confirm that it works as expected.

Automatically closed - issue fixed for 2 weeks with no activity.