diff --git a/LoopFollow/Controllers/Nightscout/Treatments.swift b/LoopFollow/Controllers/Nightscout/Treatments.swift
index b628737b4..14e9e391b 100644
--- a/LoopFollow/Controllers/Nightscout/Treatments.swift
+++ b/LoopFollow/Controllers/Nightscout/Treatments.swift
@@ -4,6 +4,39 @@
 import Foundation
 
 extension MainViewController {
+    private struct TreatmentOccurrence: Hashable {
+        let id: String
+        let eventType: String?
+        let date: Date?
+    }
+
+    /// Nightscout duplicates can have different MongoDB `_id` values. Trio FPU siblings share an `id` but have distinct
+    /// times, so deduplicate by logical occurrence rather than `id`.
+    static func deduplicatedTreatmentEntries(_ entries: [[String: AnyObject]]) -> [[String: AnyObject]] {
+        var seenOccurrences = Set<TreatmentOccurrence>()
+        return entries.filter { entry in
+            guard let id = entry["id"] as? String, !id.isEmpty else { return true }
+            let eventType = entry["eventType"] as? String
+            let occurrence = TreatmentOccurrence(
+                id: id,
+                eventType: eventType,
+                date: treatmentOccurrenceDate(entry, eventType: eventType)
+            )
+            return seenOccurrences.insert(occurrence).inserted
+        }
+    }
+
+    private static func treatmentOccurrenceDate(_ entry: [String: AnyObject], eventType: String?) -> Date? {
+        let rawDate: String?
+        switch eventType {
+        case "Pump Site Change", "Site Change", "Sensor Start", "Insulin Change":
+            rawDate = entry["created_at"] as? String
+        default:
+            rawDate = (entry["timestamp"] as? String) ?? (entry["created_at"] as? String)
+        }
+        return rawDate.flatMap(NightscoutUtils.parseDate)
+    }
+
     // NS Treatments Web Call
     // Downloads Basal, Bolus, Carbs, BG Check, Notes, Overrides
     func WebLoadNSTreatments() {
@@ -35,12 +68,7 @@ extension MainViewController {
 
     // Process and split out treatments to individual tasks
     func updateTreatments(entries: [[String: AnyObject]]) {
-        // Deduplicate entries by "id" field (Trio/Loop UUID)
-        var seenIDs = Set<String>()
-        let uniqueEntries = entries.filter { entry in
-            guard let id = entry["id"] as? String else { return true }
-            return seenIDs.insert(id).inserted
-        }
+        let uniqueEntries = Self.deduplicatedTreatmentEntries(entries)
 
         var tempBasal: [[String: AnyObject]] = []
         var bolus: [[String: AnyObject]] = []
diff --git a/Tests/NightscoutTreatmentDeduplicationTests.swift b/Tests/NightscoutTreatmentDeduplicationTests.swift
new file mode 100644
index 000000000..4c7696bda
--- /dev/null
+++ b/Tests/NightscoutTreatmentDeduplicationTests.swift
@@ -0,0 +1,64 @@
+// LoopFollow
+// NightscoutTreatmentDeduplicationTests.swift
+
+import Foundation
+@testable import LoopFollow
+import Testing
+
+struct NightscoutTreatmentDeduplicationTests {
+    private typealias Entry = [String: AnyObject]
+
+    @Test("keeps Trio FPU siblings with one id and distinct times")
+    func keepsFPUOccurrences() {
+        let entries = [
+            entry("newer", createdAt: "2026-08-16T02:06:00Z"),
+            entry("older", createdAt: "2026-08-16T01:06:00Z"),
+        ]
+        #expect(deduplicatedIDs(entries) == ["newer", "older"])
+    }
+
+    @Test("collapses duplicate Nightscout documents and keeps the first")
+    func collapsesDuplicates() {
+        let entries = [
+            entry("first", createdAt: "2026-08-16T01:06:00Z"),
+            entry("duplicate", createdAt: "2026-08-16T01:06:00Z"),
+        ]
+        #expect(deduplicatedIDs(entries) == ["first"])
+    }
+
+    @Test("uses normalized effective time and event type")
+    func usesLogicalOccurrence() {
+        let first = entry("first", timestamp: "2026-08-16T01:06:00Z", createdAt: "2026-08-16T01:05:58Z")
+        let equivalent = entry("equivalent", timestamp: "2026-08-16T01:06:00.000Z", createdAt: "2026-08-16T01:06:02Z")
+        let createdAtOnly = entry("created-at", timestamp: nil, createdAt: "2026-08-16T01:06:00Z")
+        let bolus = entry("bolus", eventType: "Correction Bolus", timestamp: "2026-08-16T01:06:00Z")
+        #expect(deduplicatedIDs([first, equivalent, createdAtOnly, bolus]) == ["first", "bolus"])
+    }
+
+    @Test("preserves missing identifiers and fallback behavior")
+    func preservesFallbacks() {
+        let noID = entry("no-id", id: nil)
+        let blankID = entry("blank-id", id: "")
+        let noTime = [entry("no-time"), entry("no-time-duplicate")]
+        let sensor = entry("sensor", eventType: "Sensor Start", timestamp: "2026-08-16T02:00:00Z", createdAt: "2026-08-16T01:00:00Z")
+        let sensorDuplicate = entry("sensor-duplicate", eventType: "Sensor Start", timestamp: "2026-08-16T03:00:00Z", createdAt: "2026-08-16T01:00:00Z")
+        #expect(deduplicatedIDs([noID, noID, blankID, blankID]) == ["no-id", "no-id", "blank-id", "blank-id"])
+        #expect(deduplicatedIDs(noTime) == ["no-time"])
+        #expect(deduplicatedIDs([sensor, sensorDuplicate]) == ["sensor"])
+    }
+
+    private func deduplicatedIDs(_ entries: [Entry]) -> [String] {
+        MainViewController.deduplicatedTreatmentEntries(entries).compactMap { $0["_id"] as? String }
+    }
+
+    private func entry(_ mongoID: String, id: String? = "shared-id", eventType: String = "Carb Correction", timestamp: String? = nil, createdAt: String? = nil) -> Entry {
+        var result: Entry = [
+            "_id": mongoID as AnyObject,
+            "eventType": eventType as AnyObject,
+        ]
+        if let id { result["id"] = id as AnyObject }
+        if let timestamp { result["timestamp"] = timestamp as AnyObject }
+        if let createdAt { result["created_at"] = createdAt as AnyObject }
+        return result
+    }
+}