Well in such case it might either be a case of your task force not covering your ports as AUH has all its ports in the Eastern Med, or the bug I described.
Regardless, it's important that you know not to leave your ports alone, as for right now there is no guarantee that you intercept the enemy task force heading for your port to blockade/raid convoys. It's annoying, but how the game functions currently.
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One of the things that inexplicably affects interception is apparently the range your ships have, so even if you have a task force with great minimum speed, they may not intercept jack**** if they have horrible range.
This may be completely wrong so don't take it as gospel, but from my experience you can have an endless number of task forces, but if they have bad range then they won't intercept most things, but as soon as I refit for more range then they all of a sudden get 2-4 battles each month, even to the point where a task force made entirely of BC could intercept torpedo boats, even though they had 29 knots of speed while the boats had 35+ knots.