Not a bug — a clearer message
The intermittent "Unexpected server response" some users hit was a Cloudflare security challenge ("Just a moment…") intercepting the admin-ajax.php request and returning an HTML challenge page instead of JSON. It's not a plugin error and not a timeout — reloading the page refreshes your Cloudflare clearance cookie and the next attempt goes through.
Change
The drop zone and EZ Delete now detect a challenge/HTML response and show:
Blocked by a Cloudflare security challenge — not a plugin error. Reload the page (F5) to refresh your clearance, then try again.
…instead of the generic error, so it's obvious what happened.
Install
Install the attached wp-ez-plugin-deploy-1.8.5.zip.