Figure 1. In the spectrum there is a new bump at 54.8Hz. It has not been there at the beginning of the year, and it isn't one of the dither lines that I am aware off. It is important to identify what is the origin of it.
The only thing that comes to my mind is the new cover of the EPRB bench. In the past there has been issues with a bump at 63Hz related to SPRB/EPRB, when EPRB was open.
This is a quick look at ENV_EPRB_ACC_Y (I don't know if this is a good witness)
It seems there is no coherence at 54.8 Hz
Maybe there are other sensors to look at.
I've ran an instance of BruCo to find coherence among more than 5000 channels with Hrec_hoft_20000Hz.
The results can be consulted here.
Unfortunately, no safe channel was found to be coherent around the bump frequencies.
The latest list of unsafe and unreliable channels can be consulted here.
