Two of these predictions were for yesterday evening and as the sky was very clear again, I covered both.
At 21:30:38 UTC (2 seconds after the nominal prediction) and almost right in the zenith for me, Lacrosse 3 indeed "flared", albeit very modestly. The short increase in brightness was no more than say 0.5 magnitudes but discernable. Below is the image (visually, the "flare" was somewhat better discernable).
On the other hand, during the second predicted time (23:12:38) Lacrosse 3 did nothing, it was steady as usual.