We changed the code to send the payload exactly the same way as it's sent to us (before, we were compacting it before sending). This meant that people that relied on the payload to be compact in order to verify webhooks (i.e they were verifying incorrectly) had verification failing. We reverted this immediately once it was reported signatures were failing for customers.
While not a bug in Svix, as people verifying webhooks correctly wouldn't have had issues, it still caused disruption to our customers and we've added tests to ensure that we now always compact the payloads going forward.