Just finished debugging an issue whereby one timer was running but another was not.
The cause was two timers with the same name, defined in convox.yml e.g.
timers: topic-download: schedule: "21 */4 * * ?" command: bundle exec rake collection:topics service: workers topic-download: schedule: "0 */1 * * ?" command: bundle exec rake collection:topics["customTag"] service: workers
IMO Convox should return an error to allow correction of the syntax, instead one of the jobs was over-ridden.