1965 Thin Quarter Same Thickness As A Dime

you can go coinsanbcanada<dot>com and go to the banknotes tab....you'll find out all/more than you want to know

If the reeds on the outside are missing and the copper appears eaten away (or if the cladding is all missing) then it may have been dipped into acid. There was a year where the wrong stock material was used (1970-D) that was dime stock.

Note the weakness of the strike? Because the stock was not thick enough, it couldn't strike up)
But images would help a lot more. If the full design of the quarter is on the coin, then it was acid dipped. But if the quarter design is partially there, then it might have been a quarter struck on a dime planchet:

This is on a cent planchet, but on a dime, the design would be even smaller on the coin.
Just grasping in the dark without images.

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I tried a couple of times and got the cropped pics with green arrows on them but it said something like there isn't anything in your file? Or directory? Or something.

The mushy details, centered design, and narrow design rim indicate this quarter was immersed in acid for a prolonged period.

Looks like it took an acid bath:

An acid "bath" can be intentional or accidental. Science experiement, sitting on the floor of a shop, other more nefarious reasons (love the sound of that word), etc.