diff --git a/internal/store/block/file/append.go b/internal/store/block/file/append.go
index 14ada2705..dab252451 100644
--- a/internal/store/block/file/append.go
+++ b/internal/store/block/file/append.go
@@ -63,7 +63,7 @@ func (b *Block) NewAppendContext(last *block.Entry) block.AppendContext {
 			full = 1
 		}
 		return &appendContext{
-			offset: last.Offset + uint32(len(last.Payload)),
+			offset: last.Offset + uint32(last.Size()),
 			num:    last.Index + 1,
 			full:   full,
 		}
@@ -196,6 +196,7 @@ func (b *Block) checkEntries(ctx context.Context, entries []block.Entry) error {
 			"blockID": b.id,
 			"offset":  offset,
 			"wo":      b.actx.offset,
+			"index":   entries[0].Index,
 		})
 		return errors.ErrInternal
 	}