What I am saying, and the CAS told us, is that the source was not identified with sufficient evidence -- any attempts by any party to guess the likelihood of any source based on insufficient evidence will be just that -- guessing without sufficient evidence. Three sources have been identified as possible. The CAS did not find any "more likely" source, but only that the evidence for one "possible" source was insufficient for them to find it was "more likely than not". The CAS did not evaluate the likelihood of any other alternatives, so the evidence for these alternative possibilities are also insufficient.
If you haven't seen it before, here is a summary of my thoughts. Sorry for the length, but as I am not bound by adopting WADA's presumptions, my doubts about the certainty of most all of the CAS findings are many:
First and foremost for context, while many find it most "plausible", I find it is simply not plausible that a sophisticated distance runner from Nike's remaining USA flagship team, would orally ingest a "low" (WADA's word) amount of nandrolone on purpose (high risk, low reward). Especially not after the Sydney Olympics in 2000 and high profile busts.
For this reason, given the sole occurrence before the CAS of a "low" (WADA's word) amount of orally ingested nandrolone (of questionable performance benefit), I would estimate a high likelihood of accidental ingestion, either unknowingly from a greasy burrito (as evidenced before the CAS), or possibly from supplements or vitamins contaminated with nandrolone (alternative scenario not presented to the CAS).
Since the CAS findings are based on unrebutted presumptions permitted by the WADA Code, rather than meeting the higher burden of "beyond reasonable doubt", some reasonable doubts must remain. Some of these doubts were before the CAS, and some were not. For those that are not, I remind everyone that Houlihan was fully sanctioned for not bringing sufficient evidence.
Now let's address your handle. Was it properly an AAF or an ATF? The CAS was not unanimous here, and the minority of the CAS Panel found a deviation from the reporting standard. Getting this wrong cannot always be cured later, simply by burdening the athlete to find the source, and then determine the specific nature of some of its ingredients (i.e. establishing the presence of nandrolone and its CIR), 1 month after the event. The probability of meeting such a burden is low, and will come at great cost in both time and money. Even less so when the likelihoods were altered temporarily, during the pandemic. This high cost and low probabilty is not just my opinion. Letsrun's expert-for-hire Prof. Ross Tucker estimated 6 months (bye bye OIympics 2021) and low to mid 6 figures (bye bye life savings), and still gave the chance of success as slim.
I also find the reasons given by the CAS for Prof. Ayotte rejecting the claim of an AAF (see bottom of 73) clearly deviate from the TDs. It is not within either TD for the WADA Lab to report based on any notion of "plausibility", or "likelihood". Furthermore, it seems highly misleading (at best) to compare Houlihan's levels to "pig meat", representing it as "more than twice exceeding the highest amount reported in literature", when the claim was "a burrito containing pork offal", and Houlihan's levels were less than 1/20th of Prof. Ayotte's own literature on pork offal ingestion. These are not appropriate questions for the WADA Lab to consider when reporting the result.
What about some of the assumptions driving the CAS intermediate findings?
Were the intact boars necessarily cryptorchids and at most 6 months old? This alternative was not before the CAS, but what about chemical castration and delayed slaughter? Due to forced shutdowns delaying slaughter, the pigs could have been as old as 8 or 9 months, enough time for the 2nd dose of the vaccine to wear off (according to Improvac's website). This would mean that one or two of Prof. McGlone's assumptions (only cryptorchids and at most 6 months old) were not valid for a short but relevant period during the pandemic.
Did the WA/AIU rebut Houlihan's claim of "offal"? Both WA/AIU experts curiously focused on a reduced claim of pig meat and stomach, rather than Houlihan's claim of "a burrito containing pork offal". It's all the more suprising given both experts expressly told us that offal can be rich in nandrolone in the kidneys, liver, testes, fat, and salivary glands. I think it cannot be an oversight that these experts limited their rebuttal to nandrolone poor meat and stomach, giving the CAS the impression of a strong rebuttal, yet falling short of rebutting Houlihan's claim to the AIU in correspondence of "a burrito containing pork offal". Even more surprising is Prof. Ayotte's representation that Houlihan's levels were 2-3x what was found in research, while concealing that her own research that disproves her by a factor of 50-60x. This would not be the first case that Prof. Ayotte misrepresented what was going on in her lab (see the case of Jarrion Lawson, and why it was overturned by that CAS panel).
And then there is the question of the pigs diet. While in normal times, pigs in the USA eat mostly cheaper corn, Prof. McGlone conceded that soy was increased in the diets during a short, yet relevant, time period. Just like for oral nor-DHEA, the GC/C/IRMS result is "fully consistent with" pigs on a diet of increased soy (or any other "C3" plants). This is why the TD2021NA says "The origin of the urinary 19-NA may not be established by GC/IRMS analysis" "if consumption of edible parts of intact pigs is invoked by an Athlete as the unlikely origin of a 19-NA finding". And yet the pseudo-endogenous result was used to establish an exogenous origin.
For these reasons, any suggestion that someone knows the likelihood of intentional doping with any certainty must be taken with a pound of salt.