Bent Prop Shaft??

[3 boys]

Hey there, first post for me. I've owned fishing boats for 25yrs but bought my first play boat last year, a 2008 Mobius LSV. It has been dynamite and with the addition of a suckg8 the wake is amazing, even with the stock 1200 lbs of ballast.
Late last fall i had a couple bolts sheer off where the prop shaft attaches to the Vdrive. Over the winter my dealer replaced them all with new stainless bolts. I put about 50hrs on this summer and what do you know, last weekend, we experience horrible vibration and 3 of the 4 bolts are broken again. I installed new ones but at idle there appears to be a wobble in the shaft. Could this be from a bent shaft, resulting in the bolts sheering off or could it be a sign of worn out cutlass bearings? or, is it normal for it to move a bit? Odd because there is no vibration when running it at all.
Thanks in advance for any insight

[DOCDRS]

year of boat would help, have you checked the alignment?