Task: Herbal Entrepreneurs doesn't let me take a plant sample

Also have this exact same issue

I have a very similar issue.

I encountered the Nexus family house (The one where you pick up Task: Broken Family) on Kadara before I acquired and tracked down the, ahem, impaired individuals who sent the SOS in Task: Emergency S.O.S. So I talked to the salarian who gave me the UV lamp and the turian with the sick friend early on. After completing Task: Broken Family, I completed Task: Emergency S.O.S. (because I already had the UV lamp), but because I already had the UV lamp, the Task: Herbal Entrepreneurs never popped up in my journal (it wasn't given when I picked it up conceivably because I hadn't started Emergency S.O.S. at the time), so I am unable to collect the herb sample from the, ah, gentlemen in the S.O.S. task.

TL;DR: Basically, my issue is the same in that I cannot collect the herb sample. The underlying cause appears to be different, however, as an issue in plot flag order seems to have made it so that I don't have the quest in the first place. 

I suppose going back to an old save might fix it, but I completed the Broken Family task on a visit that occurred some time ago, and I'd rather not lose a quarter of my total progress for a single quest. 

(P.S.: OP, I think the "memory size in GB" is referring either to your RAM or VRAM; I don't think they make 500GB VRAM devices...yet... and if you have 500GB of RAM your system must be wild indeed)

I'm playing on a Xbox, so I don't actually have the RAM specs. (Just 500GB space. Haven't upgraded yet) it was sort of a joke.

Same but on PC...so not going to click "Me too"

I can't give the drugs to the patient either. I have redone this quest multiple times with different configerations of who I talk to first, but none work. As far as I can tell a side quest called "Running a Fever' is supposed to initiate upon talking to the doctor, but it never does. I assume You can't hand the drug off unless that quest triggers.

same but on PC. no sample to save refugee even though it says it may be helpful. Just another bit of info task: Herbal Entrepeneurs is now stuck unread in my completed quest log so I think its an issue with the quest not triggering completion correctly.

The completionist inside me is dying a little.

My experience is similar, but Herbal Entrepeneurs jumped straight to my completed list with the ! in front of it.

 I'm playing on PC (edited)

My order of events (in case it helps for bug replication): 

I triggered the Emergency S.O.S. quest while exploring, but did not follow up on it yet.

I found the Broken Family location.

I talked to everyone except the salarian.

The asari gave me the quest to fix the antenna, which I did.

After completing the Broken Family quest, I talked to the salarian and got the sun lamp.

I was cleaning up other quests, and went to the Emergency S.O.S. site and encountered the grow operation.

In the conversation, I gave them the sun lamp and they said I could take a sample.

Herbal Entrepeneurs marked as complete in my completed tasks and has a ! next to it that won't go away. Also, the ! won't go away in front of the Completed Tasks folder.

I scanned the plants (it was pretty twitchy with the targeting in this one), and SAM suggested they might help (something I knew from doing the Oblivion-related quests earlier, weird narrative)

The Fever-related quest (I forget the name) will not trigger and appear in my quest list, and I can't interact with anything else in the room. I seem to be stuck at this point, a bug as far as I can tell.

Hope the details help!

exactly the same issues as shadowchasers has concisely summarised in his post better than my original one

Exactly the same problem with the quest stuck in completed with the ! Not leaving.