Particles don't stick to ocean

As seen here, particles stick to the ocean plane if I manually change the time parameter, but they ignore the plane if I keyframe it and let it play. Modifier stack is turned on. It’s a very simple setup with a plane, ocean modifier and icosphere set to emit from each vertice of the plane. Is this a bug?

Some further odd observations. I noticed that after I change it manually for a bit, and then I move the timeline marker left and right, all of a sudden it started to work in some places of the timeline and then briefly after it stopped again. At some point after moving the marker around, the particles literally exploded even tho all forces are turned off. Never been so confused

Current solution: switching from Emitter to Hair makes the particles behave as expected. However, why it doesn’t work on Emitter still remains a mystery