Differential signal turning back after jumping layers

[morzh]

The stackup is:

Sig-GND-GND-Sig, a 4-lyr board.

A diff. pair travels on the top layer (sig), drops to the bottom layer (sig) and reverses direction exactly 180 degrees. That is going right back.
Would this be bad? I am not sure it would. There are good ref planes under each signal layer.

But there might be folks who say "no going back" without proper turning.

What do you guys think?

 

[crutschow]

For low frequency signals, the signal doesn't know or care which way it goes.
What is your maximum signal frequency\?