Since NHRA Heritage JrFuel rules are ONLY Pure Alky is allowed, we are very good about alway clsing our fuel jugs after we fill our tank, because alky draws water.
I've heard cases of a jug left open can fill up the jug with water, depending on Humidity / grains of water in the air.
In the early 70's I helped an injected alky funny car and we used a tall plastic tube with what looked like moth balls to filter the alky before use to take the water out.
I have not seen those filers in years. But yes a engine can detonate with water in the fuel.
BTW Heritage JF is sponsored by ERC, race fuels and even Scott Parks has said ERC is the cleannest alky he has ever used, based on no crap in the fuel tanks after use. They double filter the fuel and then put it super cleaned barrels.
Of course we filter our fuel going into the fuel tank. And take apart & clean our fuel system after each race event. It's the first thing we do after getting back to the shop. Never had any pluged lines, nozzels, jets.
Cheers