vulkan - Device loss detected in vkQueueSubmit()

I made a project based on vulkan texture example,

derived from QQuickItem, and the node base class is QSGTextureProvider and QSGSimpleTextureNode.

I made a 3d texture to draw on the node's framebuffer.

all are ok now.

but when I copy buffer to 3d texture, I got device loss if fullscreened my app.

I add barrier before and after vkCopyBufferToImage, no any use.

I'm newbie for vukan, and don't know what's the problem, if there is no Qt's business, very sorry.
anyhow, some clue is welcome, very thanks!

step:

1. click the left-top button to refresh data, that's ok.
2. click the maximize button on the top-right,
3. click the top-left button again, device loss.