I have an auto-size text element as a parent of an image element that is set with anchors [0, 0, 1, 1] so to cover and scale together with the text.
When I change the text in the editor, the images in the editor updates its size, but in play mode, it doesn’t.
If I slightly move the text in the editor, then the image in play mode resizes correctly.
As a workaround, I added a script to the text, that makes a translation of [0, 0, 0] every frame, but I think is not the best. 