This still occurs in UE5.1
Some poor soul like me will discover this thread after tearing their hair out too.
Put your function in Construction scripts, and make sure Run Construction Scripts in Sequencer is turned on. This effectively turns each frame of Sequencer, while scrubbing, into a “tick.”
In my case, I had to have a character follow a spline path. With Event Tick, you can pull delta seconds and multiply it by a speed to get distance travelled, easily plug that into a Get Transform at Distance Along Spline and you have yourself a nice actor following a spline, over time. Well, without tick, your delta will always be 0. So in Sequencer I exposed a float and called it “delta cinematic” and just animated the beginning and end of that variable, effectively creating my own tick’s Delta Seconds by hand. Be sure to set it to Linear interpolation too.
Sequencer will re-evaluate every frame (your ‘tick’) because of rerunning Construction Scripts, and with the animated float you will effectively get the timing/Delta Seconds you need. Then at Render time, since construction scripts only run once, your actual Tick will take over and you should be fine either way.
Whew!