It seems I misremembered this story that I read years ago after eating some and feeling queasy for several hours:

To add a caveat, in 2004 when the current edition of the Encyclopedia of Fungi was launched at a National Trust property, to which 60 journalists were invited for lunch, there was an incident involving this species. On the day before, we had found a specimen of Laetiporus sulphureus in prime condition, on Oak, which was collected and incorporated, lightly sauteed, as part of the meal.

Approximately half an hour after ingestion, 6 of the 60 journalists became violently ill – vomiting, cyanosed, sweating, icy cold, with raised pulse, and very frightened. The remaining 54 suffered no ill effects.

The doctor who attended diagnosed a severe allergic reaction and the symptoms subsided after about 2 hours.

Subsequent investigation turned up research by a US-based toxicology team at the University of Berkeley, California. It had concluded that 10% of the people taking part in extensive trials, suffered these severe effects. Our experience was exactly in line with this figure.

It’s also worth bearing in mind that Laetiporus sulphureus growing on Taxus hosts, is potentially lethal.

https://blog.mycology.cornell.edu/2006/10/31/eating-the-chicken-of-the-woods/