AoSHQ has an interesting take:
It gets a little worse, tool as noted by Drew: Hispanic Representatives are now agitating for the fixes to include a more generous treatment of illegal immigrants, permitting them to buy into the "health care exchanges." And they say now they'll vote against a plan that doesn't include that.
This is over-speculating, but, if a bill is doomed anyway, then each Congressmen is freed up to make maximalist demands that will please his constituents -- it's cost free, after all. The bill is doomed, so there's no real cost as far as hurting its chances of passage; might as well show off for your partisans and special interests.
So the Hispanic caucus making an 11th hour demand might indicate they're all pretty convinced this is going to fail.
He goes on to note via correction the HC has never liked the senate bill but their timing for a vocal pushback couldn't be worse for this already teetering effort.