It seems that the new patch has put a limit to the excess of production you can use on the following production item.

Let's take a look at the example. In the first autosave you can see 2 worker clearing forest towards the capital, which is producing a Chariot and has 14/25 hammers, hpt is 7. Then I let the forest be cleared, look at the capital and see 74/25 hammers (normal speed). I add an Axeman to the production queue and press enter to end the turn. That's the second autosave. The Chariot has been produced, the Axeman has 0 hammers in, and the carryover is only 25 hammers. I expected 56 hammers of carryover.

Producing a Library after the Chariot does not change anything.

My experience is that the maximum carry-over you can have is the cost of the item being produced (though I have not tested this thoroughly).

So patch is bad??? Should I download it?

That already worked like that in 1.09. Which is why you should take care not to have your chop go towards a very low-hammer unit.

I guess is to prevent you making like multiple units in one turn from the same city.

It makes sense. Otherwise you could build 20 chariots and then complete the Apollo Program in one turn.

The only hammers that carry over are the BASE hammers, with no modifiers. To get maximum benefit from the forests, you do not want the chop to happen on the last turn of the build.