I pitched a novice agent on a non-fiction project and he signed me--with much apparent enthusiasm--after receiving and reading the proposal. The agent claimed that one of the big five was specifically interested, but just after submitting to them he advised that he would be returning to a full time position in the non-agent civilian world but wanted to continue representing the project. There had been some issues with getting timely replies on the rare occasions I reached out to him, but there was a documented relationship between this agent and the publisher so I decided to ride it out.
There was no sketchy requests for paid editing services, etc. The agency has a history of decent deals, and no negative publicity that I could find.
One of the last messages received said that a specific editor was reading the proposal, loved it, and we should hear something soon.
Communication has gone all but dark, there's been no follow up on the status of the proposal, and I'm ready to start searching for a new agent. What I'm wondering is, is there a professional way to determine if the proposal was ever actually submitted at all?
Yes, but that's the second thing you'll need to do.
The first is you need to decide what to do about your "agent."
I've yammered on the topic of "I'm quitting but still want to rep you"
Your agent could have gone back to civilian life and agented on the side without saying a word. A lot of agents have side gigs, particularly when they are new. That he told you he was leaving agenting is a signal that he's not here for the long term.
Once you decide what to do, if you've elected to find a new agent, you can query on THIS PROJECT because it looks like only one editor has seen it.
When you sign with a new agent, s/he can call the editor who has it now.
This is not something you do yourself. For starters, an editor will most likely not return your phone call.
I've had to check on projects a couple times, and it's something you do pretty carefully. In other words, leave it to someone who knows how to do it.
You're better off than someone whose project got shopped widely if you're looking for silver linings.
And just for the record: this is bad bad bad agenting.