LimeSDR USB frequency coherence across 2 devices

I’m trying to share the clock from one of my LimeSDRs to the other. I configured one SDR to use the external clock of the other, and plugged a wire from the clock out pin from the first to the Ref In of the second. Unfortunately, when I give the same 80MHz reference signal to each, and plot In-phase signals, it looks like the two are still not frequency coherent:

Ideally, I would hope these are just different in phase (which I hope to eventually fix), but it looks like the waves are oscillating at slightly different frequencies (the blue looks to have a higher frequency than the orange). I have checked from the LED description on the hardware description page, and LED7 on my second board is green, meaning it should be locked to an external clock. Any thoughts on what I may have done wrong/how to fix this?

Update to this: I did some more testing and noticed some strange behavior when my second LimeSDR is given the clock out from the first one.
Here is In-phase data and FFT plot without an external clock input (Each Lime is running off of their own clock:

Virtually the same FFT. Here is data when Lime 2 is fed the clock of Lime 1:

Quite strange, the clock seems to introduce some type of interference to the Lime that is being fed the clock.