Cover image not uploading

When I try to update an issue with a cover image, I am given a “Choose File” button. When I click it and choose the file from my computer, it shows the file name (i.e. “cover.jpg”) next to the “Choose File” button. When I click the “Update” button to confirm my changes, that image is stripped out and looks like it never was uploaded in the first place.

I’m assuming that the cover image selection button should actually bring up the Media Library browser? It doesn’t currently, and the current process is broken on my version and all of my issues just show the default cover image. I have all the latest updates to the plugin.

https://ww.wp.xz.cn/plugins/issuem/