That's not uncommon in badly-behaved SMPS parts--they generate a comb up to, like, the 200th harmonic, and PCB trace resonances select a few of them apparently at random. So you can have a 1.5 MHz switcher causing
125 MHz junk in one part of the circuit and 180 MHz junk in another.Not so easy to debug if you haven't seen it before!
Cheers
Phil Hobbs