Looping messed up when rendering out

Hello,

I have been trying to render out simple film. I started with importing Houdini particles to Niagara, the particle scene itself is looping from Houdini so all I need to do is render it out in Unreal. In Unreal viewport/sequencer the scene actually is looping, as it should, but when I render it out, I get some very odd, pretty small flickering when going from last frame to first. I thought the error was in Niagara, so tried with very simple Mograph scene from C4D and got the same problem. I`ve rendered both video files and image sequences. Checked fps and other simple things, no success. So any help from here?

Thanks!