I have enderio redstone conduit pointing into redstone clocks from ExtraUtilities2. The stacktrace points towards ElecCore, so I figured I'd open an issue here. (I have already put one up on EnderIO's github.)

Here's the log: http://paste.ee/p/kvmm1

SleepyTrousers/EnderIO-1.5-1.12#3272

and an unrelated quesiton: I see you are using Immersive Engineering, may I ask, where did you get it? I can't find the 1.8.9 version anywhere.

There are pre-releases available if you subscribe to BluSunrize's patreon.
https://www.patreon.com/BluSunrize

This is not on my end.