Took me a few days to get around to it, but here’s two SDRs tuned to 137.9125MHz (frequency for APT from NOAA18) and 152MHz (frequency I found with some pager traffic).

Though there wasn’t always a perfect correlation (I assume there are other pager frequencies in use), there were definitely instances where a pager message corresponded perfectly with the broadband signal dip at the APT frequency. This is a solid 10+ MHz away and through a SAW filter, so I suspect the dip is less overloading the SDR and more some internal gain adjustment? I had auto-gain turned off.

Either way, it doesn’t seem to impact my APT signal reception, it’s just an odd quirk.