Workers not showing up on UI or tctl | Workers not polling

Though there are 3 workers listening on the same task queue, the UI shows just one worker listed in the “workers” tab in Workflow details view.

tctl shows similar results with tctl --ns <ns> taskqueue describe --taskqueue <task_queue_name>. Just one worker.

Why would the other workers stop polling? The task slots count seems very high. Anything else I should be looking at?