It is a shit-show of monumental proportions.
More typically, thousands-of-pages-bills are only printed hours before they go to vote. In past eras, legislators were unable to read them and shirked that off to staffers who would read and summarize for them, but it became too much of a burden even for staffers at some point. They'd just read key sections.
But at the same time, as technology progressed, bills became easier to print en masse. It was possible to print them at the "last second" (figuratively, say less than 24 hours), and so less time was allotted to print them before taking things to a vote.
This is considered normal, among those who are involved, those who are knowledgeable about how Congressional procedure works.
When legislators vote a bill up or vote a bill down, they are inevitably voting on little more than the name of the bill.