Woke up to saw this today:
For educational purposes: the almost-empty block on the right (881355) looks like a typical instance of blocks showing up in short order. (#356595)
This usually happens when different miners find blocks with very little time between and so they haven't had enough time to populate the block template with many transactions yet.
"But Bitcoin blocks come in every 10 minutes!"
Yes, but only in expectations and over time. It's a probabilistic process, where the difficulty adjustment makes it harder (easier) to find blocks the faster (slower) they have been coming in over the past difficulty epoch: Sometimes blocks come in in very short order. In this case, the empty block followed 11 seconds after the previous one—but interestingly the next one came 3 seconds after that.
I suppose the answer is of the block template software nature? (one fast, one slow; one pre-populated, one not? #Ocean)
Now, what about that one on the left? (881360)
Mempool.space suggests that it's an "unhealthy" block, with transactions marked as "removed."
I can't say I know what this is, and given the insanely cheap fees the standard question emerges: Are we having a mempool problem?
Why are fees (too) cheap? And wth is a "removed" transaction?
(There's some 55k transactions in mempool.space's mempool right now, which is well below anything I've seen in like a year... so MAYBE we're crashing to zero soon?!)