A patch or two ago, Pyandonean Bottles were changed from being a white item to a blue item. This change was made so that players understood they had value and didn't throw them away.
It seems that at the same time, the drop rate was changed to be quite a bit lower. I hesitated to report it for a while, because it could have just been bad RNG for me. But I do a lot of fishing in Summerset, and at this point I am pretty confident saying there was an actual change in the drop rate. It seems to be about 1/3 of what is was.
Was this intended? Could it please be reverted?