To reproduce:
1. Open the scene
2. Change "Size" field in orthographic camera
3. Notice how canvas size does not change in Scene view (Image position in canvas changes as well)

Expected:
Canvas size changes accordingly to Camera Size, (image position stays the same in camera preview)
Actual:
Canvas size stays the same when scaling Camera size (image moves in camera preview)
Workaround:
Changing UI Scale Mode in Canvas Scaler component updates the size of Canvas (changing the size afterwards produces the bug again)
Produced on: 5.5.0b7
Did not produce on: 5.3.6p7, 5.4.1f1 5.4.2f1