What you are experiencing is called a "switching transient" noise - Wiki article:
https://en.wikipedia.org/wiki/Transient_(oscillation) . Most likely to affect VHF channels first but you didn't provide any details about WHICH channels were being affected.
The radiated electrical noise is being picked up by your antenna and just happens to overlap the affected channel(s) causing a loss of reception.
You cold try replacing the switch with a high-quality replacement and see if the issue was due to degraded internal contacts. While you're at it, check and see if the switch was properly grounded when it was installed.
Now, you made some sort of reference to LEDs in your last sentence fragment. LED light bulbs, especially inexpensive imports, have been implicated numerous times in cases of RFI, especially into VHF channels.