Driving Blueprint FX via Sequencer without entering PIE mode

I am using a mask dissolve effect from here https://youtu.be/_YTw-pFuWig

I am also creating a Cinematic, not a game so everything is driven from my Level Sequencer.

I am able to trigger particle effects from my Sequencer but cannot get this effect to work unless I use PIE or SIE modes.
ie simply animating the mask fx cube from the Sequencer does not enable the effect. I must enter PIE mode.

The attached clips should make this a bit more clear.

1 Manually dragging mask fx cube in editor (Construction Script)

2 PIE mode animating mask fx cube (Event Tick in Event Graph)

3 animating mask fx cube via Sequencer (no PIE mode)

Can any Blueprint experts help? Can this type of effect be done without entering PIE mode?

were you ever able to solve this?