Low TSH, Low T4, and Low T3 simultaneously on Levothyroxine — anyone experienced this?

I have Hashimoto’s and am on levothyroxine. Recent bloods came back with T4, T3, and TSH all low at the same time, and I can’t make sense of it.
I keep seeing coffee absorption mentioned as a culprit, but I have coffee 2.5 hours after my tablet, and more importantly — the logic doesn’t hold up. If levothyroxine wasn’t being absorbed, TSH should rise to compensate, not drop. You can’t have poor absorption and a suppressed TSH simultaneously.
So what’s causing all three to be low at once? Could this be a pituitary issue rather than a thyroid/absorption one? Anyone experienced something similar?