Okay LittleFieryOne, let's see what you got.
Nitty-Gritty:
are to be x2
The first and third sentences of your con procs have "are to be". You might want to change one of them.
Only one resident resides within the location.
You should put "occupies" (or something like it) instead of having resident resides which seems a bit redundant.
The maximum duration of an SCP-4691 event is potentially limitless.
This sentence feels off to me, I think that paragraph could be reworked to have this at the end.
In all known instances, the resident within attracts the attention of citizens on the outside.
Cut "within"
though evidence of this has yet to surface.
This should be reworded to sound a bit more clinical.
…though it is unlikely that they would continue for an extended period of without being discovered.
cut "of" or add "time" after
I creeped down the stairs.
creeped -> crept
I eventually prodded one of the sunny-side up eggs. Warm, soft. Tempting, but I still chucked it.
"sunny-side-up eggs"
it was logically when someone would serve a lunch.
Cut "a" before lunch.
I shut them tight, and hid back around the corner.
Cut the comma here, in the notes there are a lot of unneeded commas (just something to look out for).
..had been consuming a thick mixture of mucus and dust in amounts..
(1:) EW (2:) maybe use the word "vicious" instead of thick.
Proposal 4691-A
To be honest I think this note could be better, as the final bit of the article you really want this part to shine.
Opinion: This is a good piece and a thoroughly creepy anomaly, nice job! I do however think there is room for improvement of tone and execution, specifically in the conprocs/notes/final notice. That said you have demonstrated willingness to improve your article in the past and hopefully will continue to do so with this one. With that in mind and the fact the I genuinely enjoyed the piece, this was an easy +1 for me.
Good Job and best of luck!!