The k8s.io/api/networking/v1beta1 API is unsupported in the latest versions of nginx-ingress, and the API will be unsupported from k8s 1.22.0+ For future-proofing against breakage, the solr-operator should start using k8s.io/api/networking/v1 to specify ingresses.

(Note v1 has only been supported since k8s 1.19.0+, so switching to using v1 would limit solr-operator to supporting 1.19.0+, unless you add special support for using v1beta1 on earlier versions, which could get messy to maintain.)