#Bitcoin block 827527 (mined by Foundry) was only 40% full…but why would this be done when the mempool is congested? While I can’t give a definite answer, there are a few possibilities:

Maybe Foundry’s mempool wasn’t synced with the global mempool, and Foundry didn’t have access to all available transactions.

Maybe it was done for competitive reasons, smaller blocks are propagated across the network faster, which could give a slight advantage to finding the next block. (They didn’t find the next block.)

Sometimes it’s done to maximize profits, but the fee span on this block was significantly lower than its predecessor and successor blocks. Good will?

Maybe it was technical difficulties and wasn’t meant to happen in the first place…

I can’t make sense of this particular case, stacking regardless.