diff --git a/Signal/src/ViewControllers/GifPicker/GifPickerCell.swift b/Signal/src/ViewControllers/GifPicker/GifPickerCell.swift
index 99109c8670..7ad5cd99d9 100644
--- a/Signal/src/ViewControllers/GifPicker/GifPickerCell.swift
+++ b/Signal/src/ViewControllers/GifPicker/GifPickerCell.swift
@@ -166,6 +166,7 @@ class GifPickerCell: UICollectionViewCell {
             assetDescription: previewAssetDescription,
             priority: .low,
             success: { [weak self] assetRequest, asset in
+                AssertIsOnMainThread()
                 guard let self = self else { return }
                 guard assetRequest == self.previewAssetRequest else {
                     owsFailDebug("Obsolete request callback.")
@@ -176,6 +177,7 @@ class GifPickerCell: UICollectionViewCell {
                 self.ensureViewState()
             },
             failure: { [weak self] assetRequest in
+                AssertIsOnMainThread()
                 guard let self = self else { return }
                 guard assetRequest == self.previewAssetRequest else {
                     owsFailDebug("Obsolete request callback.")
@@ -187,6 +189,8 @@ class GifPickerCell: UICollectionViewCell {
     }
 
     private func ensureViewState() {
+        AssertIsOnMainThread()
+
         guard isCellVisible, let asset = previewAsset else {
             // Nothing to show,
             clearViewState()
@@ -216,6 +220,8 @@ class GifPickerCell: UICollectionViewCell {
     }
 
     private func clearViewState() {
+        AssertIsOnMainThread()
+
         imageView.image = nil
         imageView.isHidden = true
         mp4View.video = nil
diff --git a/SignalMessaging/Views/ManualLayoutView.swift b/SignalMessaging/Views/ManualLayoutView.swift
index 6b9b8318fb..b8443cc76f 100644
--- a/SignalMessaging/Views/ManualLayoutView.swift
+++ b/SignalMessaging/Views/ManualLayoutView.swift
@@ -113,6 +113,8 @@ open class ManualLayoutView: UIView {
     }
 
     func viewSizeDidChange() {
+        AssertIsOnMainThread()
+
         layoutSubviews()
     }
 
@@ -151,6 +153,8 @@ open class ManualLayoutView: UIView {
     // MARK: - Reset
 
     open func reset() {
+        AssertIsOnMainThread()
+
         removeAllSubviews()
         layoutBlocks.removeAll()
 
diff --git a/SignalMessaging/Views/ManualStackView.swift b/SignalMessaging/Views/ManualStackView.swift
index 605ba447bd..07b1bfd993 100644
--- a/SignalMessaging/Views/ManualStackView.swift
+++ b/SignalMessaging/Views/ManualStackView.swift
@@ -98,8 +98,10 @@ open class ManualStackView: ManualLayoutView {
     // We cache the resolved layout of the subviews.
     private var arrangement: Arrangement? {
         didSet {
-            invalidateIntrinsicContentSize()
-            setNeedsLayout()
+            if arrangement != nil {
+                invalidateIntrinsicContentSize()
+                setNeedsLayout()
+            }
         }
     }
 
@@ -111,8 +113,6 @@ open class ManualStackView: ManualLayoutView {
 
     public func invalidateArrangement() {
         arrangement = nil
-        invalidateIntrinsicContentSize()
-        setNeedsLayout()
     }
 
     public override func sizeThatFits(_ size: CGSize) -> CGSize {
@@ -587,6 +587,8 @@ open class ManualStackView: ManualLayoutView {
     }
 
     open override func reset() {
+        AssertIsOnMainThread()
+
         super.reset()
 
         alignment = .fill