It seems at the moment the base attack value for a Vanguard's Will is 1450 whereas before the patch it was about 1513. For example, I have +6 with a normal rating of 47% that has 4371 damage. 2.59 is the coefficient for a +6 rank and a weapon with 100% rating receives a 1.35x bonus to its damage value so 4371/2.59/(1+(.35*.47))=1450.
Now if you have a Vanguard's Will before the patch you can do the same calculation but if you remember the rating % it was before the patch it will give you a base value of 1513 instead. My one that I'm using had a 89% rating, it is +7 so it has a 3.16 coefficient at 6269 damage. 6269/3.16/(1+(.35*.89))=1513. At the moment these weapons are showing a rating % of 100 even though before the patch they were not 100% or even close.
So this means one of two things: the base attack value of Vanguard's Will have been nerfed to 1450 from 1513 but any of them already in the game were not updated to reflect this OR the base value is still 1513 but the % shown on the weapon is incorrect which means you are still able to refine them to the real 100% value of 1513*1.35=2042 (or 5290 for a +6). However I believe it's the first scenario because I just spent a lot of refiners refining the normal rated weapon where I achieved a 1% poor rating with a 3770 damage value. The fact that I achieved a 1% poor rating with this damage value is literally impossible if the base value is still the previous 1513 since the absolute bottom rating of 0% for a +6 weapon would yield 1513*2.59=3918 damage - higher than the 3770 I received.
This however leaves a third option open which is the title of this post - that refining is broken. Maybe if you refine to 100% it will give you a 100% value based on 1450 base damage and not the old 1513 whereas if you crafted the weapon it is still able to get a 100% value based on the old 1513 base damage (and instead will just show 100% rating even though it is greater than that)
If it's not refining that's broken like this then this is pretty gamebreaking imo because it means any players new or current who wish to upgrade their weapons will never ever have the ability to beat someone with an older version of the weapon that had at least 84% rating (which is quite low in itself for a min-maxed weapon): 1513*(1+(.84*.35))=1957 which is the same as 1450*1.35=1957 aka a new version weapon at 100% rating. You can see this in the game right now by hovering over someone's weapon and holding down shift - if it was an old weapon that had over 84% rating before it will show 100% now. In reality, if it was anymore than 84% rating before now the real rating is >100% because of the new base damage value.
If you made it this far thanks for reading. Hopefully the devs can give a response soon 
