I replaced a fluorescent tube in the kitchen earlier with an led tube.
I also swapped the starter with the led dummy one which came with it.
Only problem is now the switch crackles and flashes, so not ideal.
It didn’t do this with the old one- am I missing something?
I’m not home now, but is it just a case of check the wiring in the switch/change the switch or some other reason for it?

Could be a loose wire, dust or just a crap switch.
Check everything is tightened up correctly