[2020] Game crashes when enter Heoboria (or whatever you call when the stag monsters dies to fire flacon (ryelagh?)

Could you please elaborate on when this happens?

It would make it much easier for us to investigate.

I’ve been looking into this, and I haven’t been able to find any other reports of this.

Unfortunately, the most likely explanation is that game data belonging to the area you are attempting to access has become corrupted, which is causing a crash upon being accessed.

If you use the Steam client, you could try Repairing Last Epoch Through Steam. If you have the standalone client, running the Launcher should cause it to perform an integrity scan.