I've tried TI JF's on my basses; I've played them on friend's basses; this includes both 4-in-line and 2+2, flat and angled back headstocks; and I have been wrapping strings properly all the way down tuning posts since 1976. I'll be blunt: in my 45+ years of playing bass, TI Jazz Flat A strings suck. Even La Bella found that out. The first iteration of their LTF's were to compete with TI's. So they copied them, albeit in stainless flat wrap instead of nickel, including making a similar loose A string. It was so bad that after a couple of years La Bella reformulated the A string from a 70 to a 75 to better balance the set. TI needs to do the same thing.
I see. I haven't noticed any kind of loose rubber band feeling out my A string is all.