This issue has persisted into the 20w11a.

Fly around in a creative mode jungle on version 1.15.2 ocelots spawn fine. With the glowing effect applied to entities they are easily found with just a minute or two of exploration.

Try the same thing in a 20w10a jungle and ocelots are not appearing. Have spent hours combing 20w10a jungles. Ocelot spawning is broken.

Attached is screenshot from 1.15.2 where three glowing ocelots can be seen through the brush and a screenshot from 20w10a where no glowing ocelots can be seen (because they never spawn!).