What triggers the edit can't be applied problem when editing your nominations?
Back in the early days of Ingress' "Operation Portal Recon", you couldn't edit your submissions once they had been submitted. Now we have Wayfarer, and your nominations can be edited - at least as long as they are still in the "queue" and have not yet gone into "voting" (in my opinion, these would be better be labelled "pending" and "voting", but I digress).
However, if I try and edit my nominations/submissions, often I get an error saying my edit can't be applied, and I have never been able to figure out what causes this. It's not age - yesterday I successfully edit a submission 995 days old (that got an upgrade immediately afterwards, and now, one day later, has already been turned into a portal); but some other submissions from the same time I couldn't edit successfully.
It's also not anything to do with numbers of characters - which are now helpfully shown to you. Nor is it to do with copy-and-pasting versus manually typing your edits.
What causes some edits to be disallowed, and some to go through?