Black strides issue when scaling window(issue only shows when d3d11 is for SDL2 rendering)

I try to use d3d11 for rendering a video,
SDL_SetHint(SDL_HINT_RENDER_DRIVER, “direct3d11”);
when scaling the window(zoom in or zoom out) by using cursor to drag the right bottom corner, there will be a horizontal black stride at the bottom and a narrower vertical black stride on the right. It seems that the video is shifted to upper left of the window, then leaves the black strides at bottom and on right of the window.
If I drag the title bar to move the window, the bottom black stride and the right black stride disappear.
This issue happens if only I use d3d11. If I do not set d3d11, there will be no such issue. Is there anyone who encountered the same issue? Any solution? Thank you!