Hello,
Here is a bug I found while trying to use varnishes. I tried to use a varnish on my weapon and the message read "You cannot cast from stored items" . . . but then it subtracted a varnish from my pile of stored varnishes i.e. writs of storage. More details below
Where: I was on the screen just north of outskirts near the fire beetles den
When: Today. I was able to duplicate the error twice and probably could have continued duplicating the error if I chose.
What: I had 18 Strong Scorching Varnishes (Stored at Vallaki Warehouse) and I accidently clicked on the varnish to use it on my weapon and got a message that said "You cannot cast from stored items." Then the stack went down to 17. I tried it again and got the same message "You cannot cast from stored items." and then my stack went down to 16. So in essence, I was losing varnishes that were supposed to be in storage and there was no effect on my weapon.
Recreate: Simply get a stack of stored varnishes and try to use them on a weapon or armor and watch to see if the inventory is depleted without the desired effect. Maybe it's isolated to "Strong Scorching Varnishes" that are stored, but I suspect not
Here are screenshots:
