all vCPUs are not connected in systems running low on resources, for example in a virtual machine with 1 vCPU + 256 MB of RAM,

docker run -ti --runtime kata-runtime --rm --cpu-quota 30000 --cpu-period 10000 busybox sh -c "sleep 5; nproc"

returns 2, when the expected result is 4 (1 cold plugged vCPU + 3 hot plugged vCPUs)