`complete-symbol` not working consistently within a roam document

I am a frequent user of completion in org-roam (I have org-roam-completion-everywhere set to t). I use a fairly vanilla installation of doom-emacs, and a recipe pulling the latest version of org-roam, so I complete by calling complete-symbol via M-TAB while in edit mode).

Lately, I’ve noticed that in a few documents, completion seems to be working in an inconsistent way, namely if I type a particular prefix (PL, in the example below, which should complete to [[roam:PLR]]), it will autocomplete in some headlines (and associated text) but not in others, with no indication as to why it succeeds in one case and fails in the other. See the following example for an illustration:


Here, when I try to complete in the first headline, it fails “No Matches”. The same thing happens in the text below the headline.

However, if I try to do the same thin in the last headline or associated text, it properly opens up the suggestions menu and allows me to do the completion.

I am not very good with elisp or emacs debugging, but I am fairly certain through instrumenting the complete-symbol function that eventually it calls org-roam-complete-at-point in both cases. I am unable to distinguish why it then succeeds with retrieving completion options in one case and not in the other.

Any suggestions as to how to troubleshoot this or further debug it would be welcome.