TypeError: Cannot read properties of undefined (reading 'split')

[sentry]

Sentry Issue: FLAGSMITH-FRONTEND-4NB

TypeError: Cannot read properties of undefined (reading 'split')
  at Utils.validateRule (./common/utils/utils.tsx:798:39)
  at <anonymous> (./web/components/modals/CreateSegment.tsx:361:33)
  at Array.find (<anonymous>)
  at <anonymous> (./web/components/modals/CreateSegment.tsx:361:20)
  at Array.find (<anonymous>)
...
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