well for some strange reason it happens I have made 8 calls at a time same board and 1 or 2 just don't have it first thing is tear bad ones apart check all measurements if good re glue hope for best ,,I would say if some one says evey call they build is good They are just shipping anything out door build enough calls and when u pick up a square blank youll know what u have to tweak inside to get desired sound light wood or heavy
after finish do u check the height of your sound board ? the slight finish my make a difference I always sand mine clear after finish same way with ledge surface sits on take razor clean finish on then double check your heights
in any glue joint you don't want to squeeze all glue out me I use a heavy weights hear of lots guys using soup cans ,, me I get in a routine glueing not to much not to little I like give a half twist after setting surface in and center it . if it locks tight ( cant move surface) to ledge after twisting theirs not enough glue I use syringes to me that's best way get good contestant bead and again u do enough it becomes easy
I glue sound board let weight sit at least 8 hrs . When I do surface 12 hours before I even try play no way that glue is dried ,,,IMO you run them before glue dry u make things loose IMO no call will sound the same if u run it 2 hrs after glue up compared to 12 hrs Glue dried ,,leason learned LOL