Thank you for using the correct vowel for your context. A pet peeve of mine is when people misuse flesh and flush. Flesh is adding to a body of work. Flush is removing unnecessary details from the work. One adds flesh to bones (an outline, draft, etc.). One flushes crap down the toilet, getting rid of it.
Yes one should write flesh out rather than flush out. However, as someone who uses English as a second language, the concept of phrasal verbs is the single most non-intuitive thing (with the very real risk for severe faux pas).
From your own words, to flesh out implies to me as a non-native that I remove flesh from said thing, when in reality the expression is to mean that you "add" flesh to bones. Very confusing.
> the concept of phrasal verbs is the single most non-intuitive thing
I once said that a person seemed pretty "turned on" when I meant "switched on". Luckily it was on a private conversation with a friend who laughed and took the mickey out of me but then explained the situation so no harm done.
Are you saying that you’ve heard people say something like, “let’s flush this out”? I’ve never heard or read that before.
Although, “let’s flush this out” is also a hunting idiom, as in flushing out game. So that may be part of the confusion.
Never heard that either, and I've mostly worked in professional settings where there wasn't many native English speakers, but most of the communication was in English anyways, and don't recall hearing/seeing that once. And I'm usually slightly bothered by those silly things too.
"I created a story in Jira. Next refinement session we need to flush out the details."
To which the Jira bot should automatically reply, “We need to flush that sentence— and Jira— down the toilet.”
I once had an exterminator flush out an animal from my attic.
Who wants details in Agile/Scrum anyway? Flush them out! /s