Water based gloss yellowing

[Michaelsf90]

About 18 months ago our front room and back room was redecorated. When it come to glossing we sanded. Undercoated a couple of coats. Then a couple of coats of dulux water based gloss. In some places it seems to be yellowing? Is this normal? It seems to be worse like say their is a dream catcher on the wall that overhangs a glossed casing. How do I stop it yellowing? Was it not sanded enough to remove the oil in the old gloss? I thought water based didnt yellow

 

[Michaelsf90]

This door has half the bottom part blocked by a unit/cabinet. So it's got restrictive light. How can I stop this yellowing or what paint would be best suited?

 

[sparkwright]

Was the undercoat oil-based or water-based?

Some water-based wood finishes can go very streaky in a relatively short time - so water-based isn't always the answer.

 

[Michaelsf90]

Water based? I've noticed its spots where very little natural light can get to it. I'm going to try johnstones aqua based next time as its suppose to be top stuff