did you store them for a time or somesuch before using them? if so that may be the cause. it happened to me yesterday as well. boiled varuious schrooms to use in shroom legume salad. ate them in glutton session got poisoned. these were store for 2 hours in a box before being used in a recipe.
i have read that this happens more often here and there. and mostly with morels.
Boiled some witchhats, made shroomrolls, gobbled them within a time frame of 30 mins and still got 3/4 of the shroom poison debuff from gobbling 4 rolls. Shrooms are so dead for me if they need boiling (doesnt work out anyway).
And oh yeah, reboiling them doesn't work right ? At least i can't make out any progress when doing so.
We might as well implement real time spoiling of stored food right ?
Another fun fact is when you have your max inspiration cut to below what you currently have!