Render manager - jobs stuck 'waiting for nodes'

We are having a little trouble with our farm recently. Had been perfect since setting up, but 6 month-ish later we are now getting jobs stuck in the queue. There are machines in our farm available to rendering, but the job stays stuck on ‘waiting for nodes’ and the nodes are saying ‘searching for task’.
Wierdly, if we send the exact same job to the queue again, it will start rendering straight away, but the first submission just sits there doing nothing. There are no errors showing at all with these hung jobs.

The 2 possible ideas I have, but Im not a pro in these things, are either short interupts in our network/internet connection. Or maybe the anti-virus our company uses. It is the ‘endpoint’ suite. I include this as we had major trouble with a protection program and backburner in the past.

many thanks in advance

EDIT
Through some testing we have found that a job will start rendering if we send it twice. The first one sits waiting for nodes for eternity, the 2nd starts like normal.

Please check this for the possible causes: https://www.pulze.io/faq/my-render-manager-jobs-are-waiting-for-nodes-but-my-render-nodes-are-idle-and-ready-to-work.-what-can-i-do

If nothing in the faq helps then please install this nightly build that will solve this problem: https://public.pulze.io/pulze-downloads/pulze_service/2.1.4/pulze_214_win.zip

Sorry, I forgot to add in my original post that the jobs had no errors posted at all.
Everytime I have checked the Admin tab, a computer has been assigned as the distributer. Although I guess this doesnt rule out the nodes themselves losing network connection.
Thankyou for the nightly I will try this and post back.
Many thanks

This seems to be working at the moment. Can I ask what the patch actually addressed? I wondered if it was something we were doing wrong at our end

The patch in version 2.1.14 should fix several job distribution and job logic bugs.
For example if you had 5 single frame jobs where for one of the nodes made an error on the first one, it would create a jam and none of the jobs below will start.
From the information that you provided it was definitely the Render Managers fault.