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Fatal Error: Duplicate keys...

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Some of my users exprience from time to time crash of the app. From Firebase Crashlytics I see that error message:

Fatal error: Duplicate keys of type 'Contact' were found in a Dictionary. This usually means either that the type violates Hashable's requirements, or that members of such a dictionary were mutated after insertion.

Basically Im retrieving from API array of CallLogs which I have turned into dictionary with this following code to have nice grouped logs by date, contact

private func logsByDate() {

  let groupedByDate = Dictionary(grouping: logs, by: { $0.date.removeTimeStamp ?? .distantPast })

  let groupedByContact = groupedByDate.mapValues{ (dateArray : [CallLog]) -> Dictionary<Contact, [CallLog]> in
    return Dictionary(grouping: dateArray, by: { $0.remoteParty as! Contact })

  DispatchQueue.main.async {
    self.groupedLogs = groupedByContact

I was not able to reproduce this error on my device. Is there a way to fix this?


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