It is most definitely hacking. After a fight like that, if the shield is as strong as you say it might be, you would think he would’ve lost half a ring of shielding at the very least. But nope, he was still at 100% shields after being shot for 4 minutes by an anaconda and even rammed at a couple parts. That definitely is not legit.
The lack of damage to the Krait in the second half of the video (despite most of the packhounds being used against it not having time to arm) does strike me as unusual, but even if there is something going on that shouldn't, absent other evidence, hacking is not more likely than a myriad of other possibilities.
If the OP thinks a report was warranted, that's prudent, but claiming it's 'most definitely hacking' is unfounded.
So how is it that a bi-weave Krait didn’t lose even half a ring of shields while being shot for 3 minutes and even rammed a couple of times by an anaconda, but a Prismatic Mamba in that same video loses a whole ring of shields in a matter of maybe 30 seconds to that same anaconda?
Reinforced biweaves and resistance boosters can result in quite a bit of kinetic resistance (the bulk of the Anaconda's damage) and guardian boosters could mean a relatively large total shield pool.
It's also quite possible, even likely, that damage was in fact not registering as it should, ether on the OP's end, or for both parties. This could be caused by quite a few known bugs, latency compensation, or some other connection/instancing issue. I've seen far stranger stuff occur where I was completely confident no manipulation of the game was taking place.
Hell, it could even be the result of hacking...that's just not the only possibility, and the focus on the SLF, which behaved entirely normally, likely inspired the same sort of dismissive snap judgements against the OP's claim as you seem to have for any explanations that don't feature hacking.