it really varies from roll to roll and manufacturer and colour to manufacturer and colour.

I have some pla filaments that if left on the machine overnight, will have broken between extruder and roll by morning, and some that can be left almost indefinitely without any breakage.

One of the problems is that there is no legislation on what additives go into 'pla' filament.
We have absolutely no idea what anyone puts into their mix and no legal way of finding out.

And also the colourant has a significant effect on all aspects of the the filament.

Then there's each persons 'workshop' enviroment. Temps and humidity vary, so a filament that for one user has no issues might cause problems for someone else.

I find with pla, that if it gets brittle, it tends to only be the first 8 - 10 inches or so.

Also, brittle pla snaps at the first bend.
Normal pla will take several bends to snap.

So it sounds like there is nothing wrong with the original posters filament.
It was just that first outer layer that was brittle, all the 2-3 bend stuff - was perfect :-)

You have to bear in mind that pla - while beaing seriously durable, is also very hard, so it won't flop around like nylon or abs. Stress it enough and it will snap.

But if it doesn't snap on the first bend - then use it, it's fine :-)