the two bolts are not tight because they are not positioned correctly ,
the heads of the bolts kind get wedged in to a small cutout on the column tube when properly assembled .
when you tighten them the friction gets them tighter and the stay in the cut out.
the collar has probably turned on the tube so the alignment slots are not catching the heads of the bolts.
I have seen bent collars also cause this .
if it were me i would take the whole thing out and slowly take it apart , using the diagram break down picture from a old year one catalog you will see how it is assembled also gives opportunity to clean and lube the lower bearing if its not shot .
PS the upper bearing is mounted in a rubber gromet or sleave not really pressed into turn signal collar.