Toilet cistern fill valve , washer fitting question

[andyr123]

first time i have had to replace a washer in this type toilet cistern. It all seems to be working fine , however as the cistern is filling up water is dripping out where I have arrowed as its filling , after its finished filling the water stop coming out of that place … should it do that though or is the washer not seated/fitted properly?
Also another oddity now when the cistern has finished filling it kid of 'farts' now LOL , thats the only way I can describe the sound it makes. I never noticed that before. - the brief noise seems to come from the top of the valve area. - sounds like air releasing, is it suppose to do that?

 

[CountryFan]

No it shouldn’t make that noise, but it looks like it’s catching on the side of the cistern. I can’t remember how these fill as I’ve not changed one for ages. I think water does drip from there.