I found two separate bugs in GCP products. One with gVisor where it would sometimes null-truncate large network packets (this was very hard to diagnose – why is my JSON full of null bytes?) and one where Cloud Run broke sudo sporadically (sudo in a FaaS is definitely niche, I had essentially containerized a very old application written by undergraduates).

Both times they were serious production bugs that took at least a week to resolve, though I only had the lowest tier of support package.