The one she uses on the Oathgate was Pattern though, as dead Blades aren't supposed to work? The Truth came later. I would have to get my poor old copy of WoR to confirm but I also think she changed the Blade's size in the chasms, while cutting out the shelter.
I got a new idea about that end-of-RoW Truth, not sure if it's been brought up or maybe obvious to some, but could that Truth have been to Testament, not Pattern? It was mentioned Testament looked better afterwards, but at the time I wasn't sure why.
I certainly agree about drawing conclusions about Lightweavers from Shallan, not only is she unreliable but there's also the double bond situation now messing up things.