diff --git a/layout/generic/nsFlexContainerFrame.cpp b/layout/generic/nsFlexContainerFrame.cpp
index 73ffc6a7dfa8..3c23a32e8c1a 100644
--- a/layout/generic/nsFlexContainerFrame.cpp
+++ b/layout/generic/nsFlexContainerFrame.cpp
@@ -2348,6 +2348,10 @@ void nsFlexContainerFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
                                 nsIFrame* aPrevInFlow) {
   nsContainerFrame::Init(aContent, aParent, aPrevInFlow);
 
+  if (GetStateBits() & NS_FRAME_FONT_INFLATION_CONTAINER) {
+    AddStateBits(NS_FRAME_FONT_INFLATION_FLOW_ROOT);
+  }
+
   const nsStyleDisplay* styleDisp = Style()->StyleDisplay();
 
   // Figure out if we should set a frame state bit to indicate that this frame
diff --git a/layout/generic/nsGridContainerFrame.cpp b/layout/generic/nsGridContainerFrame.cpp
index 7e17a3a9869c..a65bee28ee97 100644
--- a/layout/generic/nsGridContainerFrame.cpp
+++ b/layout/generic/nsGridContainerFrame.cpp
@@ -7493,6 +7493,10 @@ void nsGridContainerFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
                                 nsIFrame* aPrevInFlow) {
   nsContainerFrame::Init(aContent, aParent, aPrevInFlow);
 
+  if (GetStateBits() & NS_FRAME_FONT_INFLATION_CONTAINER) {
+    AddStateBits(NS_FRAME_FONT_INFLATION_FLOW_ROOT);
+  }
+
   nsFrameState bits = nsFrameState(0);
   if (MOZ_LIKELY(!aPrevInFlow)) {
     bits = ComputeSelfSubgridBits();
diff --git a/layout/reftests/font-inflation/reftest.list b/layout/reftests/font-inflation/reftest.list
index ea9ecc974a44..47e277b2bb73 100644
--- a/layout/reftests/font-inflation/reftest.list
+++ b/layout/reftests/font-inflation/reftest.list
@@ -90,9 +90,9 @@ test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceE
 test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-cell-2.html threshold-scope-cell-2-ref.html
 test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-cell-3.html threshold-scope-cell-3-ref.html
 
-fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-1.html threshold-scope-flex-container-1.html
-fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-2.html threshold-scope-flex-container-2.html
-fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-grid-container-1.html threshold-scope-grid-container-1.html
+test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-1.html threshold-scope-flex-container-1.html
+test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-2.html threshold-scope-flex-container-2.html
+test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-grid-container-1.html threshold-scope-grid-container-1.html
 fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-items-1.html threshold-scope-flex-container-items-1.html
 fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-flex-container-items-2.html threshold-scope-flex-container-items-2.html
 fails test-pref(font.size.inflation.emPerLine,15) test-pref(font.size.inflation.forceEnabled,true) test-pref(font.size.inflation.lineThreshold,100) == threshold-scope-grid-container-items-1.html threshold-scope-grid-container-items-1.html