Hey I'm still a complete newbie in the Korean language, but maybe I can still help a little.
That question refers to their conversation on page 13-14 of chapter 82, and is at the same time open enough for additional interpretations.
Warning:
In the next comment there will be spoilers for chapter 82 and a rookie's monologue about Korean. ╮( ̄∇ ̄") ╭
So on page 13 Jung Yohan leans in for a kiss, but Park Moogyeong rejects him because they are still outside.
Yohan then asks on page 14:
괜찮지 않아요 ...? (gwaenchanhji anh-ayo ...? )
= "Isn't it okay...?"
The structure in Korean is more like: ''Okay(it's fine) is it not?''
Maybe you already know that the Korean word for ''(it's) okay''
= 괜찮아 (gwaenchanh-a )
or
전 괜찮아요. (jeon gwaenchanh-ayo.)
=> ''I'm fine.''
In the same speech bubble he proceeds:
사람또 없고 어누워서 하나도 안보이잖아요 . (salamtto eobsgo eonuwoseo hanado anboijanh-ayo.)
= ''There aren't any other people, so you can't see anyone/anything.''
Moogyeong-Hyung answers with:
안괜찮아,임마. (angwaenchanh-a, imma.)
=''It's not okay, man.''
'angwaenchanh-a' = negation of gwaenchanh-a = Not-okay
('imma' is translated as 'hey(as an exclaimation like 'ya')/dude/man'
=> This is what the 'okay' (gwaenchanh-a) refers to in his question.
(To be continued in another comment)
Johan prefaces the question to his hyung , on page 17, with:
말 나온 김에 물어보는 건데요.
(mal naon gim-e mul-eoboneun geondeyo.)
=translated by the team with: ''Speaking of which, let me ask you this,"
Now to the most important sentence.
So the question in split into two speech bubbles, but because the English sentence structure differentiates from the Korean, the order of the words in the translation is the exact opposite of the original.
In the Korean RAWS the first part of the question, on the bottom of pg 17, Yohan begins with:
괜찮을때가 (gwaenchanh-eulttaega)
alone that part means => ''When is it okay'' or ''When it is okay''
Again you find the 'gwaenchanh' = okay (just without the a at the end)
and the addition of 'eulttaega' = 'when'
The second part of the sentence on pg 18 reads:
있긴 했어요? (issgin haess-eoyo?)
= ''There was?''
'issgin '= ''there is / is there ?''
'haess-eoyo?'= ''Did (you)?'' => or just an intensification of a sentence like ''?!''
Thus, putting it all together, the question is:
괜찮을때가 있긴 했어요? (gwaenchanh-eulttaega issgin haess-eoyo?)
= ''Have you ever been fine/okay (with it)?''
(In korean an extra 'with it' isn't needed to make the question complete)
So Yohan asks Moogyeong:
''Was there ever a time when it was okay/fine?''
He refers to their previous discussion -
>When is it okay (qwaenchanh-a) to show his affection? Was it ever okay, or always a burden/inconvenience to his Hyung? <
- and maybe even the whole relationship:
Was Moogyeong ever really 'fine' with it?
I'm sorry that these comments are so drawn out
and of course for all mistakes in the spelling & translation too! Σ(  ̄□ ̄||)
Although I'm neither a native English speaker nor a Korean,
I hope you found something helpful in this, bluerobintail.
In a nutshell, languages are diverse and fun haha
Have a nice day! (▰˘◡˘▰)
I wish I spoke Korean and could refer back to the original text.
‘Have you ever been okay’ doesn’t make much sense as a question in English.
But then again, maybe the question is just as vague and awkward in the original...