Yes. If you ship any eBPF programs that utilize kprobes and/or read kernel structures that change between kernel versions, you have portability problems. See https://facebookmicrosites.github.io/bpf/blog/2020/02/19/bpf... for a good overview of the problem that CO-RE intends to solve.
Ah! That makes so much sense. It hadn't occurred; when we rolled out BPF at Fly, the first thing we did was commit to standardize our kernels. After all, there's not much CO-RE can do about your BPF compiler not having tail calls, or not allowing bounded loops. But we're almost entirely XDP; I can see kernel structs being a much bigger problem for people doing observability work.