Flare is when RPM spikes, not drops (reduced torque window is gone, engine starts to push, but the clutches in transmission are not engaged yet). What you see and feel is a torque converter lockup: starting from 3d gear transmission first shifts with open TC then a second or two later it gradually locks the converter (SLU modulates the lock) so it has a direct gear now, without torque transferred through fluid. It does it in 3d, 4th and 5th gears.
It's best to display gear, SLT/SLS/SLU and S1-5 solenoids in VIDA when you diagnose your transmission. VIDA has a limitation of how many of them can be displayed at the same time. My "mini-DiCE" does not have that limitation, you can clearly see what transmission is doing:
And a ton of other information from ECM, DEM, CCM, REM.
