I believe that the assumption is that the player have already posted in the 1st reporting thread with the screenshot.
You can't "still" have problem if you never had the problem to begin with. And in their mind, if you didn't report the problem in the 1st thread in a timely manner like you "should", that would be your fault.
And I would think that as long as you have qualifying screenshot in either thread, the comp can be sent.

The fact that a time stamp is required makes sense, seeing that you could have them reset for the week, finish them all by Thursday, then take a screenshot. While it should be possible to verify by some backend log whether you simply finished them for the week or it didn't reset, they are probably too lazy to bother and therefore conclusive screenshots are required. Given that, I doubt any screenshot made after 10:00 server time on the 16th would count, because that is the earliest time at which people can finish all the TI of the week if it reset. (well, it takes some amount of time to finish 5 runs for the day, but the amount o time required is difficult to estimate, so for simplicity, that's probably the cut off)
By the same token, they probably won't care much about the SA screenshot, but instead working off of the TI screenshot mostly.

That said, just because it makes sense doesn't make it fair, if it wasn't required in the original requirement, it should never be required ever.

Personally, I think they should also accept the screenshot if the post that contains the screenshot was made in the correct time frame (and not edited after the time frame). While it is POSSIBLE that the screenshot is taken from a previous week, it is unlikely, not lots of us keep such screenshot around. So in all likelihood the screenshot was taken near the time of post and thus reflect the problem of the time, even if the screenshot itself have no time stamp. It's something I feel they should honor.

Neither post mentioned anything about compensation, both claims to be attempt of resolve. The only mention of compensation was raised by the 100 coupon etc stuff for a different bug. I'm fairly sure that talk of compensation for the TI bug was not raised until it was too late (i.e. after Thursday 10am)

I'm too lazy to go through every page but...
The first thread contains 36 pages, made in a bit under 2 days
The second thread only 23 pages
And given the "valid" screenshot time frame, only 12-15 pages of the second thread is useful, as any post past that will likely contain a screenshot that is taken too late, even if they asked for screenshot (unless they already have one and only posted later)

In any case, if done right, log data should be able to be used to find who was active but haven't done any TI/SA that week. Thou this does have some problems, it is far better than depending on screenshots. It should have been theoretically easy to compile a complete (or almost complete) list of all affected players before Thursday 10am in that week, just a set of queries that look for those with 0 remaining TI chance should have done it. This is certainly a value that is stored in some sort of database, so it should be able to be pulled up. Granted, this might require help from the actual dev of the game and not something Oasis could do. But bit over 3 days should have been more than enough to get whatever help they need.

Which was made on the 16th, the Thursday, at 8pm. LA servertime(the latest server)
That is entirely too late for any new screenshot to be taken, as there is no way for them to verify using the screenshot whether the player didn't get a reset or if it's simply been done for the week. And if they are going to verify via log, then screenshot would not be a thing in the first place.

So that post is entirely useless regarding the need of screenshot.

And I would agree with that.
I'm merely pointing out Oasis's logic for requiring one and their tendency to blame the player for not filing a proper report (among other things) when something goes wrong and the basis they will use for this blame.