One of my sub-user is not getting a prompt to load the encrypted key when viewing submissions.

I've added a sub user and shared forms with them, I've given them the key to open the encrypted forms but Jotform never ask for it and only shows them the encrypted data (gibberish).

Just tried it with my sub-account and I was prompted to upload the key.

Please ask the sub-user to use other browsers or clear their browser's cache then try again.

Let us know how it goes.