Broken Link Checker 1.11.19 & 1.11.20 Crashing Sites

The Broken Link Checker team responded quickly to release version 1.11.21; they have confirmed it should resolve the issue. 🎉

If we take care of your updates, we’ll be updating your site shortly!

If you normally take care of your updates, we recommend updating as well. Note, versions before 1.11.17 have a security vulnerability – so please be sure you’re now running version 1.11.17, 1.11.18, or 1.11.21.

The recent versions of Broken Link Checker are causing sites to get overloaded and crash.

Please do NOT update to 1.11.19 or 1.11.20. If you’ve already updated, we recommend deactivating the plugin until a new version is available with a fix.

We’ve seen this on three different hosts, and it has been reported to the developers here:
https://wordpress.org/support/topic/causing-php-processes-to-remain-open/