Well, not really specific to Curado....can be any reel of a similar design.

You get all saddled up, get to your spot and give 'er the grip 'n rip.
Then all you get is a loud squeal and your offering only goes about 1/4 of the distance it normally would.

Also it may be the first cool day in the Fall or early Winter.

I would switch to a backup reel and then do a teardown/clean/re-lube on the squealer later.
Never was able to isolate the exact cause and the reel would be fine after service.

This fall the squeal came back and I had a theory.
Took the spool out and placed a drop of water on the bearing that is captive on the spool shaft.
Normal performance on the next cast and for the rest of the day.
Water is a lubricant and it was just enough for that bearing to stop chattering.

So, the squeal is from the captive spool bearing.
Carrying some light oil would be a better plan, but water works in a pinch as long as you're not in freezing temps.

Shimano actually recomends ya keep it dry. Very close tolerances. For years I was using too much oil. Reels are quiet now and cast better

DD - Thanks for the tip. My reel is doing the exact same thing. I will try some bearing oil (hot sauce) to see if that fixes it.

Never heard of this and I've been working working on Shimano baitcasters since the mid eighties.

I think that the spool shaft end bearings could lock up and revert to bushing mode.
They wouldn't squeal, although they were suspects at one time.
I don't think that the larger spool bearing could revert to bushing mode.
This is the squealer, IMO.

More theory...
If you're an aggressive caster, this bearing wears and clearances open up.
When the bearing dries out it will "chatter" when that immediate spin- up occurs with a hard cast.
"Chatter" = squeal
I believe that a new, dry bearing would not squeal under the same conditions.
It's just such a beotch to get that bearing out as it's behind a pressed in cross pin. Easier to keep it oiled.