Hmmm
I'm not sure, I notice that sometimes if I do it too many days in a row, the effects are definitely lessened until I take a break for a day or 2. But like you said you use it every few days..
If it's the same batch of Pouni Ono/Borongoru I reckon it's not a bad batch.
Although i'm sure you already are doing these things, just to cover all the bases: make sure you're drinking your Kava on an empty, or near empty stomach. That has a HUGE impact on what effects you'll get. I notice if I drink with any bit of food in my stomach, euphoria is lessened by like 75%, and the relaxation is lessened quite a bit. Also ensure you're staying hydrated. Before I drink my Kava I like to down a glass or 2 of water, just to sort of prepare my stomach for it, it should get things moving and help clear out the stomach so the Kava can absorb a bit quicker and better. After I drink my Kava I have some form of electrolytes to replenish, and the day after I replenish with some more electrolytes. I'm not sure why electrolytes are so important in the Kava experience, i'm aware it's a strong diuretic, but if i'm out of electrolyte supplements I notice Kava is hardly pleasant. I get real edgy, the effects are more agitating than soothing, it's really odd. Though, that very well could just be me. But it couldn't hurt to try and hydrate a bit more
Another thing is you could just try switching strains. One thing i've absolutely noticed is when I first try a new strain, my body reacts way more strongly to it than Kava i'm used to. I used Kava Supreme for a while, and I kind of stopped "feeling it" from that Kava, and as soon as I switched to Melo Melo the effects were much, much more pronounced. Now I tend to go back and forth between strains, I always have a few on hand. Right now my favorite is Melo Melo, but I still have some Supreme, and some Borogu. I've also got a few Kava capsules on hand.
You could try swapping strains if the lack of effects continue, I know that worked for me. But, everyone is different!
I'm sure others will chime in here as well. I wish you best of luck