For all of FX Collection 2...
When using Logic 10.6.1...
When you click the "lightbulb" icon to show tooltips & callouts...
And you turn a knob to increase db, etc...
The callout (which shows the exact db adjustment that you are making) will not appear if the track is not playing.
The callout will only appear if you hit play.
This behaviour of the callout is different from other plugins (where the user expects to be able to see the exact value of a knob/parameter adjustment, even if the track is not playing).
UPDATE (June 24, 2021):
Perhaps this is only a problem in Logic, because if I load FET-76 in another host, and then turn FET-76's Input knob, the callout always appears. That is, if I turn the Input knob from left to right, the callout correctly displays the knob's increase in gain from -48 dB to 0 dB. But, in Logic, the callout only appears when the track is playing, not when the track is stopped.
Attached is a screenshot which shows the callout that I am referring to (it says "Input Gain: -34.6 dB" in the screenshot). This screenshot is of FET-76 version 1.2, but I am also seeing the problem that I described above in the latest version 1.3.