It is clear you've considerable experience soldering, in general, and BGA's.
Someone knows why the balls don't wet to the paste "mound" though they
collapse as typical. My question remains considering whether this "mound"
wets, or not, to the solder termination pads. If it does not wet their
either (in addition to the balls), what is of primary concern - provided
your profile is as you say (looks ok for some pastes considering the 185 [56
seconds may be low] window and liquidous [how much time here?]?

You know the heat is concentrated at the BGA corners. If the profile is low,
your corners may wet while edge balls do not - or may be wetting marginally.
Still feel uncomfortable with ball collapse but not wetting to the "mounds."

Earl Moon

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