diff --git a/tsdb/head.go b/tsdb/head.go
index 5663e3cf9..fc09d232f 100644
--- a/tsdb/head.go
+++ b/tsdb/head.go
@@ -636,6 +636,7 @@ func (h *Head) loadMmappedChunks(refSeries map[chunks.HeadSeriesRef]*memSeries)
 		if !ok {
 			slice := mmappedChunks[seriesRef]
 			if len(slice) > 0 && slice[len(slice)-1].maxTime >= mint {
+				h.metrics.mmapChunkCorruptionTotal.Inc()
 				return errors.Errorf("out of sequence m-mapped chunk for series ref %d, last chunk: [%d, %d], new: [%d, %d]",
 					seriesRef, slice[len(slice)-1].minTime, slice[len(slice)-1].maxTime, mint, maxt)
 			}
@@ -650,6 +651,7 @@ func (h *Head) loadMmappedChunks(refSeries map[chunks.HeadSeriesRef]*memSeries)
 		}
 
 		if len(ms.mmappedChunks) > 0 && ms.mmappedChunks[len(ms.mmappedChunks)-1].maxTime >= mint {
+			h.metrics.mmapChunkCorruptionTotal.Inc()
 			return errors.Errorf("out of sequence m-mapped chunk for series ref %d, last chunk: [%d, %d], new: [%d, %d]",
 				seriesRef, ms.mmappedChunks[len(ms.mmappedChunks)-1].minTime, ms.mmappedChunks[len(ms.mmappedChunks)-1].maxTime,
 				mint, maxt)