I received NAVS today, from staking, about 2 days worth, before that it was very slow, and even couple of transactions that didn't go through.

IMHO nothing is wrong, just big volume of NAVS being sold and bought, so it takes couple of days. In the long run you should get 5% exactly, nothing more nothing less, so calculate it for yourself.
If the percentage was much higher than 5% for some time, you will receive nothing for couple days.