I am a little north of you and mine is doing the same, but it is only 3 years old. Weather issue? Going to feed it better next spring.

I assume you know how to check each one for ripeness? Forgive me if you are already well versed on this, but I was surprised when I started growing pomegranates, how difficult it was to gauge ripeness -- I had to look up several methods and use them in conjunction.

Anyway, the ones you describe with the bland-tasting white seeds to me just sound under ripe. You can't really rely on supposed harvest dates since each fruit will ripen at its own time due to the fact that flowering, pollination, and speed of ripening are not synchronized in pomegranate the way they are for many other fruits (especially temperate zone ones).

Hope this was helpful.

I go by the matte finish to the skin with flattened sides, or if they are split.

Echo nm and matt. My parfiankas are the leading taste POMs. But, they must be mature.... and not overly so.