You said - " I have some Azaleas that are starting to yellow a little."
This is a classic symptom of a plant about to make new growth, (ie - not a
problem), possibly because of the recent rain. It is also that time of the
year when Azalias start to 'grow and shed' for their pre-winter flowering.
Sit back and observe! And maybe another feed in a month or two, this is my
experience.

China
Wingham
NSW