Agent_proxmox_ve breaks checkmk 2.5.0 when no subscription is present

How can I verify that the MKP’s version of the special agent is used? I’ve added and enabled the extension and for good measure restarted checkmk, but checking the Proxmox host still fails with the same error:

Traceback (most recent call last):
  File "/omd/sites/monitoring/lib/python3.13/site-packages/cmk/server_side_programs/v1_unstable/_crash_reporting.py", line 96, in wrapper
    return func(*args, **kwargs)
  File "/omd/sites/monitoring/lib/python3.13/site-packages/cmk/plugins/proxmox_ve/special_agent/agent_proxmox_ve.py", line 531, in main
    return agent_proxmox_ve_main(parse_arguments(sys.argv[1:]))
  File "/omd/sites/monitoring/lib/python3.13/site-packages/cmk/plugins/proxmox_ve/special_agent/agent_proxmox_ve.py", line 328, in agent_proxmox_ve_main
    for name, content in _create_node_sections(
                         ~~~~~~~~~~~~~~~~~~~~~^
        node,
        ^^^^^
    ...<6 lines>...
        data,
        ^^^^^
    ):
    ^
  File "/omd/sites/monitoring/lib/python3.13/site-packages/cmk/plugins/proxmox_ve/special_agent/agent_proxmox_ve.py", line 391, in _create_node_sections
    node_total_cpu=node["maxcpu"],
                   ~~~~^^^^^^^^^^
KeyError: 'maxcpu'

Failed: 'maxcpu' - please submit a crash report! (Crash-ID: ecaf5786-4c96-11f1-8000-bc2411a8ad4d)(!!)