SCP Foundation

If they have to resort to less conventional means of containment (trailing it), it should have been Keter from the get-go.

That aside, I find this current version to be weaker than the draft I've seen some days back. 2590-2 makes little sense; it is a slab containing the blood of the people it killed by crushing them. I don't see any reason why it should be a sub-designation.

I believe that SCP-2590 can be safely assumed to be self-aware.

Given that you have highlighted that it is driven by 2590-1, it can be assumed from the get-go that a sentient force (the driver or 2590-1) is controlling all this.

There are some promising elements to this - the build up of items in the truck is decent, if a little slow - but I don't think the current ending works. "Murder then disappearance" seems a little too pat for something that could have gone in almost any direction - I was hoping it was merely another step towards a more complex resolution, but you could live without it entirely.

Agree that the ending isn't gelling with the rest.
To me it feels like a non-ending of the weak sort; you build it up with the interesting logs and hints of more going on… and then it kills two agents and is never seen again. That sort of "so we still have no clue what's going on here" ending can work, but it's very hard to pull off. Kudos if you can make it happen, but sometimes a little bit of explanation can go a long way. Right now you're ending on a weak answer: "it doesn't like the Foundation", when you could be ending on a strong question ("what does this thing really want, and why?") or even following it down the rabbit hole into higher planes of weirdness.

One of the Foundation's specialties is applying scientific curiosity to the anomalous, trying to figure it out:
Can they attach a tracking beacon to it to figure out where it goes when it isn't active?
Maybe weld it in place, so it's considered part of the vehicle and won't get left behind?
If they figure out where it goes, what do they find there? Further weirdness? An anomalous warehouse? A normal parking lot?
Can they put a tire boot on it, or remove its tires so it cannot drive off, or tow it away?
Can they get a better look at the driver by flying a drone-mounted camera directly up to the window?

I like the idea behind this SCP. Nevertheless the second incident - in my eyes - does not fit into the story. It seems a bit weak in contrast to the other findings.

Therefore I vote neutral.

Edit: after the changes it is an upvote for me

I still find that assuming the intervals are random isn't actually supported here. I think you want "unpredictable intervals" or "based on currently unknown variables" or something. AFAICT, there's no reason that the Foundation would have to assume a statistically random process as more likely than one based on variables that aren't known to them. It could be random, but it also could not be, and given that very few things in reality are actually random, it probably isn't.

The idea you have here is definitely executed well and kept me interested, but the tone and grammar could use some touching up (especially in the object logs).

The revision you did changed my initial neutral vote to a tentative upvote though.

EDIT: The newest revisions you've done have confirmed a solid upvote from me. Well done!

Technically competent, but goes absolutely nowhere and otherwise has no payoff. Feels like a cobbled together collection of parts.

I agree with the popular sentiment that this suffers from a weak and incoherent ending that doesn't work well with what comes beforehand. It's competently written and there's promise to the idea, but the ending is too simplistic to sell the story.

SCP-2590 is a semi-trailer truck of an unknown make
Going by the pic, it's a late-model International ProStar® tractor in DayCab configuration.

Made a bunch of edits, hopefully for good this time. I changed the end result as well.

Thanks for all the feedback, folks. I really do appreciate it.

EDIT: My sandbox has a bunch of additions I have made to the plot, hopefully for better. I would like feedback before adding them to the main article, so please, let me know what you think.
Link: http://scpsandbox2.wikidot.com/multiscoop

EDIT EDIT: Made changes to the sandbox that Scorpion451 so kindly helped with, and put them into the article. They are designed to give it more story. Also fixed a bunch of unclear sentences, and added the manufacturer bit.