if you fall asleep with heavy sleeper trait and a critter is writing (text bubble is showing the ... animation) you'll still see if for a while after waking up even if the critter is not writing anything

the only step you need to do is fall asleep while someone is writing, probably anything that makes you unconsious works too

Edit.

Had a related bug later, so this one might be on my end, not sure if it could be replicated by other person yet