X-rated Bob wrote
That's a very fat third string. Normally with a set that runs from 56 to 12 you'd have a wound 3rd - and the core would be a lot lighter, probably lighter than the plain 2nd and possibly lighter than the 1st. I wonder if the sheer fatness of that plain 3rd is part of the problem here.
Quite possibly. There may not be enough tension for a decent down pressure on the saddle and a thick unwound string is stiff, but not necessarily high tension. Is the tailpiece cranked down low enough that there is a good break angle over the saddle?
