ver.1.3.4 #9483459 Turn 11
Here you couldn't topdeck a Mandarin with a Royal Seal which was forced by the Mandarin's when-gain to leave play but had already been triggered. You should be able to resolve the Royal Seal for the Mandarin, though not for gains afterwards. Yes, this is a bug unless an ancient ruling
is reversed. See the post while articles on Wiki (Mandarin
and Royal Seal
) are ambiguous in this respect.
I'm not sure of other situations but I find online has correctly some similar things where two effects are triggered at the same on-buy and one's resolution eliminates the other's condition in the meantime. For example, Inherited Estate as Mint+Hoard in Turn 12, Mint+Talisman in Turn 13, and Talisman+Haggler gaining Mandarin in Turn 15).
Edit: Sorry, I made a wrong title. Corrected.