Sixspeedsquirrel

So I will do my best to keep this brief. I rode a friend’s 2015 FJ-09 a couple weeks ago, because I was considering buying one. I loved it, bike ran great, “A Mode” was scary fun, “B Mode” was muted but still fun, and I love the total package. Fast forward to today, and I had negotiated a purchase of a used 2019 Tracer 900 GT with 6,000 miles, at a Kawasaki dealer. I traveled 300 miles to buy it, but on the test ride I noticed something funny about the way it ran. In A Mode and STD Mode, the power felt restrained in the mid-range, almost like it was choked off. Not bucking or cutting out, just a little down on power. When I switched to B Mode, I noticed it was the fastest one! These problems were present with the traction control set to Off, 1, and 2. The salesman rode the bike and confirmed B Mode is the fastest, but he doesn’t really know what may be causing it (it was at a Kawasaki dealer, so not their product). For my own analysis, I counted off the time it took to accelerate from about 4,000 RPM to almost redline. In B Mode it looked like 3.5-4 seconds. In A Mode and STD Mode, it was 5-5.5 seconds. I chose not to buy this bike. The dealer would not budge on price, and I am inclined to think this could be an ECU issue (so unknown cost of repair, etc). I searched and could not find any record of anyone describing this particular issue on the FJ-09/Tracer, though I know many folks have experienced a wide range of fueling issues with the stock ECU. Does anyone have any other suggestions as to what might cause these problems?