A regression in the handling of custom resource data was reported last week that impacts Kubernetes versions 1.23.0-1.23.2.
In the affected Kubernetes versions, Custom Resource Definitions that specify x-kubernetes-preserve-unknown-fields: true on fields containing list items and do not set it on the individual items schema, incorrectly drop unknown fields inside those list items. The issue has been fixed and will be resolved in 1.23.3, which is targeted to be released tomorrow (2022-01-25).
If you use Custom Resource Definitions that make use of the x-kubernetes-preserve-unknown-fields: true feature for list fields, we recommend you wait to upgrade until 1.23.3+ and avoid the following releases:
If upgrading to 1.23.3+ is not possible, the issue can also be mitigated by changing the Custom Resource Definition schema to set x-kubernetes-preserve-unknown-fields: true on the items schema instead of (or in addition to) the parent property schema to continue preserving unknown fields inside the individual items.