[15.4.1 Windows 10] Video clip Opacity has no effect on non-Normal Blend Modes?

[XilburQost]

I'm layering several video tracks, and for one of the upper tracks I have set the Effects Blend Mode to Overlay. I want to fade this track up from zero opacity to 100% over a period of severals seconds. To this end I'm using keyframes on the Opacity setting. The problem is that while the fade-up works fine when the track's Blend Mode is Normal, when I change it to Overlay, or to any other non-Normal Blend Mode, the Opacity setting appears to have no effect, i.e., the Opacity appears to be 100%. Is this by design? Or am I missing a step? Thanks.

Windows 10 Home v2004 OS build 19043.1165 v21H1

[Ann Bens]

Works fine here:

FAQ: How to reset (trash) preferences.

[XilburQost]

Thank you for the tip. I reset preferences, but the behavior is the same. 

[XilburQost · Accepted solution]

I think I've figured it out. The problem track was the bottom-most visible track, i.e., it was overlaying black. Make a track below that visible and the Blend Overlay Opacity settings work.

Meanwhile, I found that applying a Cross-Dissolve to the start of the problem track (instead of adjusting Opacity) achieves the effect I want.