Essentially, yes. The problem with "statistical inference" is that is does not stack. Logical inference can be stacked as high as you want and the end-result (unless you made a real "hard" error in applying the rules) will always be valid. With "statistical inference", that is not true. Each step only has a probability smaller than 1 to succeed and that is fundamental. At some, not very high, number of steps, the results become arbitrary. Hence the "feat" here is that the LLM found the result to be very close in reach with regards to inference steps.
So, why did no Mathematician find this? Simple: Mathematicians are smart and look at things that are intuitively promising, given a real understanding of the overall picture. In rare cases (and we have one here) that results in cutting of a short, but not intuitive and hard to see inference path. That is also the reason some coding models find very old bugs: These bugs were hard to spot for humans with actual general intelligence and insight, but relatively easy for a strongly limited inference mechanism that has no understanding at all and just tries simple (but non-intuitive) things in order of probability until it succeeds.
Example: The recently hyped FF bugs found by Claude Mythic were two use-after-free (and one more, 2 of 3 only "medium level, and about 20 others found by humans at the same time, which gives you an idea how much Claude covers in relation to human review) and these can be found completely automatic with, e.g., gcc -f analyzer or other tools. Not impressive, but apparently nobody used quite conventional tools or real code review to find these and they are _easy_ to spot. Other example: CURL, where Claude found one security bug (and 4 false positives) in a code-base that realistically will still have more like 100 left (which given the code size would be pretty good), but all not obvious to a human that looks for things that make sense and most (excluding that singular one) not within reach for an LLM either.
The whole thing, including this story here, is full-on lying by misdirection to keep the investor money flowing. Unfortunately, most people are not smart enough to understand what is going on and how utterly limited LLMs are. Well, _those_ people may be within reach of being replaces by an LLM, at least partially.