on minecraft 1.11.2, forge 2298. RebornCore 2.14.2.94, TechReborn 2.2.1.142, Actually Additions r107.
this happens:(solar panel is full but mfsu is filling)

TechReborn/TechReborn#1083

This is very likely a problem with TechReborn, since the lasers only transfer the power and if they work fine with other machines they could't be the problem

hey ah, i don't know how did i do it but i tried it in vanilla, TR + RC + AA, and laser relay doesn't work. so this gif happens only in my modpack i think. dunno what causes that infinity problem. but if you make a clean install with TR + RC + AA, laser relay won't connect the energy from solar panel to MFSU.
edit: yeah, it happens in my modpack (infinite energy connection) but in the vanilla. in vanilla it doesn't even work.

I have no idea what this is about, so I'm going to wait on what @modmuss50 says.

I bet it's a TR issue, especially if it's fine with other mods. There is an issue open on our tracker about so I can look into it. If it turns out to be your issue I will get back to you. This can be closed.