Possible workaround for crafting bug
So I've dismantled a sword in which I put some runestone, after that these two Perun runestones appeared in my inventory, obviously. But then I noticed that I was able to craft a greater Perun runestone all of a sudden since now the crafting menu recognised these two lesser runestones I got through dismantling. I then tried dropping all my other runes and glyphes and picking them back but that didn't help unfortunately.
So dismantling swords or armours with runes or glyphes in them seem to be a workaround for the crafting bug.
So I've dismantled a sword in which I put some runestone, after that these two Perun runestones appeared in my inventory, obviously. But then I noticed that I was able to craft a greater Perun runestone all of a sudden since now the crafting menu recognised these two lesser runestones I got through dismantling. I then tried dropping all my other runes and glyphes and picking them back but that didn't help unfortunately.
So dismantling swords or armours with runes or glyphes in them seem to be a workaround for the crafting bug.