Batch rendering order may go wrong if batch's first node gets invisible

See the attached code and QSG_RENDERER_DEBUG=build log.

The visibility of "HigherText" is unchanged, but it blinks along with the wide "@" icon (order: 2).
That's probably because the "Batch 0" (order: 5) overwrites the "Batch 1" (order: 3, 4, 7).

This is the batches when the wide "@" is visible:

{{Alpha Batches:

• Batch 0 0x7f31b4055eb0 upload root: 0x0
• element: 0x7f31b400a6c0 Rect( 254 280 402 428 ) node: GeometryNode( 0x7f31b400ca40 strip #V: 4 #I: 0 x1= 0 y1= 8 x2= 148 y2= 156 materialtype= 0x7f31d77bea62 ) order: 1
• Batch 1 0x7f31b4057610 upload root: 0x0
• element: 0x7f31b400a848 Rect( 70 310 570 384 ) node: GeometryNode( 0x7f31b400cf90 strip #V: 4 #I: 0 x1= 0 y1= 0 x2= 500 y2= 74 materialtype= 0x7f31d77bea62 ) order: 2
• element: 0x7f31b400a7a0 Rect( 253 84 388 219 ) node: GeometryNode( 0x7f31b402a6c0 strip #V: 4 #I: 0 x1= 0 y1= 0 x2= 135 y2= 135 materialtype= 0x7f31d77bea62 ) order: 5
• Batch 2 0x7f31b4057490 upload root: 0x0
• element: 0x7f31b400a730 Rect( 455.471 248.722 585.567 272.27 ) node: GeometryNode( 0x7f31b4010dd0 triangles #V: 36 #I: 54 x1= 0.619141 y1= 7.72217 x2= 130.715 y2= 31.27 materialtype= 0x7f31d77becf9 ) order: 3
• element: 0x7f31b400a768 Rect( 455.471 188.722 585.567 212.27 ) node: GeometryNode( 0x7f31b4011720 triangles #V: 36 #I: 54 x1= 0.619141 y1= 7.72217 x2= 130.715 y2= 31.27 materialtype= 0x7f31d77becf9 ) order: 4
• element: 0x7f31b400a810 Rect( 251.432 139.48 390.606 170.48 ) node: GeometryNode( 0x7f31b402b050 triangles #V: 40 #I: 60 x1= 0.619141 y1= 6.47998 x2= 139.793 y2= 37.48 materialtype= 0x7f31d77becf9 ) order: 7
• Batch 3 0x7f31b408dd30 upload root: 0x0
• element: 0x7f31b400a7d8 Rect( 348 229 419 300 ) node: GeometryNode( 0x7f31b402ab00 strip #V: 4 #I: 0 x1= 0 y1= 0 x2= 71 y2= 71 materialtype= 0x7f31d77bea62 ) order: 6
  }}

And this is the batches when the wide "@" got invisible:

{{Alpha Batches:

• Batch 0 0x7f31b4057610 upload root: 0x0
• element: 0x7f31b400a7a0 Rect( 253 84 388 219 ) node: GeometryNode( 0x7f31b402a6c0 strip #V: 4 #I: 0 x1= 0 y1= 0 x2= 135 y2= 135 materialtype= 0x7f31d77bea62 ) order: 5
• Batch 1 0x7f31b4057490 root: 0x0
• element: 0x7f31b400a730 Rect( 455.471 248.722 585.567 272.27 ) node: GeometryNode( 0x7f31b4010dd0 triangles #V: 36 #I: 54 x1= 0.619141 y1= 7.72217 x2= 130.715 y2= 31.27 materialtype= 0x7f31d77becf9 ) order: 3
• element: 0x7f31b400a768 Rect( 455.471 188.722 585.567 212.27 ) node: GeometryNode( 0x7f31b4011720 triangles #V: 36 #I: 54 x1= 0.619141 y1= 7.72217 x2= 130.715 y2= 31.27 materialtype= 0x7f31d77becf9 ) order: 4
• element: 0x7f31b400a810 Rect( 251.432 139.48 390.606 170.48 ) node: GeometryNode( 0x7f31b402b050 triangles #V: 40 #I: 60 x1= 0.619141 y1= 6.47998 x2= 139.793 y2= 37.48 materialtype= 0x7f31d77becf9 ) order: 7
• Batch 2 0x7f31b408dd30 root: 0x0
• element: 0x7f31b400a7d8 Rect( 348 229 419 300 ) node: GeometryNode( 0x7f31b402ab00 strip #V: 4 #I: 0 x1= 0 y1= 0 x2= 71 y2= 71 materialtype= 0x7f31d77bea62 ) order: 6
• Batch 3 0x7f31b4055eb0 upload root: 0x0
• element: 0x7f31b400a6c0 Rect( 254 280 402 428 ) node: GeometryNode( 0x7f31b400ca40 strip #V: 4 #I: 0 x1= 0 y1= 8 x2= 148 y2= 156 materialtype= 0x7f31d77bea62 ) order: 1
  }}