Cannot read property 'smembers' of undefined

[Calebe]

I'm getting this error randomly:

You have triggered an unhandledRejection, you may have forgotten to catch a Promise rejection:
TypeError: Cannot read property 'smembers' of undefined
    at /app/node_modules/worqr/src/worqr.ts:748:22
    at new Promise (<anonymous>)
    at Worqr.getExpiringWorkers (/app/node_modules/worqr/src/worqr.ts:747:16)
    at Worqr.cleanupWorkers (/app/node_modules/worqr/src/worqr.ts:762:21)
    at Timeout._onTimeout (/app/node_modules/worqr/src/worqr.ts:131:18)
    at listOnTimeout (internal/timers.js:537:17)
    at processTimers (internal/timers.js:481:7)