Thanks again for the reply. I managed to find the issue and deployed a fix - player should be taken to monastery now after failed fight with Ignisar.
The other bug with restart and botched save might be harder to find but hopefully that's very rare case.
I think I understand the problem with potions better now. Making them cheaper might throw of the balance too much but I have another idea - adding the "Tent" item. You would buy it in the shop and could use it outside of fights to rest/heal.