Which artefact does TTHnew suggest?
Make a list for Google team. keep it concise... not like this
(1) CCS is Shanahan's grand name for errors caused by cell condition changes altering calibration
(2) While everyone knows this Shanahan pointed out that some LENR papers were ignoring the fact that small call errors of this type get amplified by the ratio between the (external) power in and the (observed) excess heat out. This is pretty obvious, so that for example a 10% excess heat result will be invalidated by a calibration shift (caused by some change in conditions) of only 1%.
(3) There is then the matter of what could cause calibration to change by 1%. Shanahan hypothesised ATER (at-the-electrode-recombination) which LENR guys have uniformly stated is not possible. Well, Shanahan argues that it could be possible in certain special cases whn you have the right electrode preconditioning etc. Sound familiar? ATER has the potential to cause calibration changes by altering the position in the cell where heat is generated. For certain types of closed cell, where a recombiner is used at the top of the cell, it is plausible that moving from recombiner heat to electrode heat would move calibration consistently in the direction of less heat lost and therefore more measured.
(4) From my POV this mechanism does not apply everywhere, but a wide class of LENR expereriments need to be aware of it and check carefully. Good enough calorimetry will reduce this problem to low levels, and some LENR experiments provably have this. Shanahan thought that all such claims should check for this possible error mechanism explicitly: other LENR authors argued that "they had checked and it was obviously not an issue".
(5) From my POV "obviously not an issue" is not good enough when you have surprising results - like excess heat beyond chemical. You need to prove that such a hypothesis does not apply in every specific case that you cite.
(6) The discussion thus is more about "does ATER exist" and "could ATER alter calibration" for specific experiments than it is about CCS. One thing that has sometimes annoyed me is that LENR papers do not always (or even usually) assume what I consider a proper burden of proof. Thus if some error mechanism has been shown not to be relevant in some cases it is assumed not relevant in all cases without careful argument. Because LENR excess heat is found to be erratic, it can be simulated by an error which only happens occasionally, hence the checking for what could possibly be an error needs to be very careful.
(7) Therefore I side with Marwan et al in that there are various good ways to rule out ATER, some of which clearly apply to some LENR experiments. I side with Shanahan in that not all of the considered important LENR experiments, as documented, do rule out ATER.
(8) Shanahan argues that possibly all replicable FPHE observations are due to ATER. I don't have a view on that, it is not entirely clear what constitutes a replicable observation, given teh FPHE effect is hypothesised to depend on not easily determined electroe conditions that cannot be fully controlled nor measured, except by the apparent existence of FPHE. That makes a lot of people seeing FPHE, but not consistently, potentially fit an error mechanism that oes not always apply, but does sometiems.
(9) Were I wanting to prove FPHE effects as due to above chemical heat production, I'd need to examine the ATER and CCS issue very carefully and list those results which could not possibly be due to it (perhaps because the come from a 99% efficient calorimeter and show excess heat above errors of >> 1%). My reduced list of experiments could then be examined for other possible errors etc. At the enmd of this process the experimenst that stand up would justify Jed's and others certitude.
(10) Shanahan got annoyed with the LENR community because the published (and personal) replies to his hypothesis were dismissive without engaging fully in his arguments nor understanding them. For example, Marwan et al argue (amongst many other arguments) that CCS might lead to random errors which go both positive and negative, but these are not observed. Shanahan rightly pointed out that this was, if it existed, a systematic error mechanism, and therefore any argument about random errors does not apply. He felt that such a gross misunderstanding of his published idea showed they could not have read his paper when replying to it.
Now after that background: note my tense in the sentence you quote: conditional. I cannot prove that CCS exists. Shanahan claimed he had, from analysis of provided unpublished data, strong evidence for it in one case. Obviously that is not proven. Even if CCS does exist it would be surprising for it to apply in all cases. If CCS exists there might be some other condition change causing it, not ATER. But, ATER as hypothesised has the potential to create CCS (obviously) since it alters cell temperature distribution which may create calibration changes.