Altering servers fails if SSL is enabled

The following command (and possibly all others as well) will fail with a Cannot alter SSL at runtime error if SSL is enabled.

maxctrl alter server server1 persistpoolmax 10

The configuration that reproduces the problem:

[server1]

type=server

address=127.0.0.1

port=3000

protocol=MariaDBBackend

ssl=true

ssl_ca_cert=/home/markusjm/ssl-certs/ca.pem