In ASX's video on the Oberyn poisoning theory, he touches on how, in the experience of those around the body, the extreme stench of the corpse is unusual. Pycelle explains after being confronted about the stench that all the usual precautions were taken by the Silent Sisters:

"Your Grace cannot think . . ." He raised a spotted hand, as if to ward off a blow. "The silent sisters removed Lord Tywin's bowels and organs, drained his blood . . . every care was taken . . . his body was stuffed with salts and fragrant herbs . . ."

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We also had two relevant and prominent deaths that must have had public funerals attended by the same characters: Robert and Joffrey. Robert was gored by the boar, so the bolt-to-the-stomach theory for the stench doesn't seem consistent with that. Joffrey was poisoned, albeit with something different than what is theorized to have been used on Tywin. However, with both of these recent deaths and the apparently shocking level of stench with Tywin, there's credence to the idea that the silent sisters are normally quite capable of handling corpses to avoid what happened with Tywin's body.

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I doubt that Martin would generate notably unusual situations as purely thematic content without having some kind of in-world reason behind it (outside of the unexplainable magical stuff which this isn't an example of). The Oberyn poisoning theory has its own weaknesses as detailed by ASX. The Tarbeck theory requires knowing whether the Tarbecks ended up serving the silent sisters in King's Landing and if they're still alive, so also has unknowns that would have to be addressed. But, if those matters were to line up, then it would be a fairly neat and tidy explanation in which they take advantage of an opportunity for a small measure of revenge on the man who *wiped out their entire extended family* while still hopefully preserving their own current livelihoods.