I think there is also a lot of pressure from funders to be the first to provide proof of a paradigm-breaking discovery, and tout it as a breakthrough before the claims can be verified.
By chance, about a decade ago I met the lead researcher of a NASA group that in 2010 made a shocking claim of arsenic being incorporated into bacteria's DNA in place of phosphorus at Mono Lake, CA. They later had to retract the statement after others were unable to replicate. But the research I did into the follow up indicated that NASA, who employed the scientist, did not have its astrobiologists follow basic standard microbiology protocols against sample contamination, and pushed the arsenic hypothesis as a game-changing breakthrough before it had been subjected to peer review.
By chance, about a decade ago I met the lead researcher of a NASA group that in 2010 made a shocking claim of arsenic being incorporated into bacteria's DNA in place of phosphorus at Mono Lake, CA. They later had to retract the statement after others were unable to replicate. But the research I did into the follow up indicated that NASA, who employed the scientist, did not have its astrobiologists follow basic standard microbiology protocols against sample contamination, and pushed the arsenic hypothesis as a game-changing breakthrough before it had been subjected to peer review.