I am randomly looting sparks from this setup, I don't know how to reproduce it, and I don't know what's causing it to happen, but somehow I keep finding sparks on the ground.

It seems to be happening when I logout and then log back in, here is what I got today:

Can you upload your world for me (and modlist so I know what to run)

Also, what version?

I had something similiar to this happen a couple of time in one of the 1.8.9 versions. Could not really figure out what was causing it though.

Here are the mods and here is the map,
Alternatively you can join me on my server just PM if you want the IP.

I'm having a similar issue and I think it's when the chunk unloads/reloads that it happens

That would be my guess as well, however it doesn't happen every-time, so there's still some unknown.

Just going to chime in and say it's happening for me as well on 1.10 minecraft server. Only when logging in. It's as the previous people here said. Appears to happen on chunk unload/reload. Latest release version (r1.8-312)

Let me know if you still have this issue in the next build