I see a couple of problems with your BP:
- You’re calling second timeline from Update method, should be used Finished unless you want to reverse at any point
- I don’t know what value you’re using in your timelines, but seems like you’re just inversing position in second timeline, you should just lerp between two positions when using Relative Location. Like from 0 to 150 and then from 150 to 0.
- Here is a quick setup with single Timeline. Value in Timeline just goes from 0 to 1 and used as alpha between 0 and Height
