Diagramless Minis

Question

Standard diagramless crossword rules apply:
Black squares will have rotational symmetry, all words are 3 letters or longer, and no letters are unchecked.

Across clues are in the correct order, but Down clues have been alphabetized.
As an additional hint, each grid will have fifteen black squares.

Hmm... it looks like there's something wrong with the instructions above.
If you read off all of the circled letters (left to right, in grid order), you will find what a certain word in the instructions should be changed to. This should help you extract a single three-word final answer.

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This puzzle is available as a Google Sheet.

Clue transcriptions:

1:
Across:
Sounds heard from someone who doesn't know the right words
Verbal exams
Hoisting mechanism
Hallucinogenic drug
Greek dawn goddess
___ Gras
Ingest slowly, as a drink
Blemish

Down:
Candy whose name includes something needed to connect the two halves on the final answer
"Exodus" author Leon
Fall, in a way
Goal
Himalayan mountain guide
Stench
Utah's capital, for short
You might hear one at night

2:
Across:
Brief affirmation
"___ my case"
Italian scooter brand
Summer clock setting in NYC
"___ queen slay!"
Corrective eye surgery
Grilled, on Mexican menus
Set one's teeth into

Down:
Comcast or AT&T, e.g.
"___ Got a Secret"
Helping hand
Inflamed
Reggae or calypso kin
Research site
Spends the night in
Thus, in Mexico

3:
Across:
Snake
Some cubes
Freeway entrances
Serena Williams' org.
Mentalist Geller
More agile
Certain article of clothing
Dash lengths

Down:
"___ a stinker?" (Bugs Bunny line)
Chinese Disney protagonist
Defeat, in a way
"Get lost!"
Gets ready, briefly
Legume
Prior to A.D.
Term of respect

4:
Across:
Wedding words
Pleasant place
Ineffective
Health resort
Also
Constrictor snakes
Female sheep
Pink Floyd guitarist Barrett

Down:
Brainstorms
Ctrl+Alt+___ (Loss meme origin)
Distress signal letters
Letters on a medicine bottle
Male offspring
Monodactylous, like horses
Rte. 66, e.g.
See

Answer 1

The three-word answer to this tricky but rewarding puzzle is:

HIDE AND SEEK!

First of all, if we follow the instructions, we are able to fill the four grids as follows (replacing the given circles with red shaded backgrounds):

My process for filling these was chaotic at first and I didn't make too much headway, as I hadn't at all clocked the useful stipulation that 'Across clues are in the correct order'! This, combined with the fact that rotational symmetry with an odd number of clues means that the centre space will always be blacked out gave me the starting points to work out from the middle rows - since all clue answers must be 3 letters long or more and there are no unchecked letters, to make a fully connected grid the middle two Across clues must always be 3-letter words positioned either side of the central blank.

The grids above are the results, and the circled spaces (shaded red here) spelled out SEVENTEEN.

So how does our instruction change?

We need to change the notion that there are 'fifteen blank spaces' per grid to one of having 'seventeen blank spaces' instead!

How to do this? Well, to preserve the other properties of the grids, in any grid there must be...

Two spaces in rotationally symmetrical positions containing letters that can be removed from the grid and replaced by blanks.

What this means in effect is that there are clues amongst those given which have been written in a way that they have two meanings that differ by the addition of a letter! These are:

Grid 1: [H]UMS → UMS and [H]OWL → OWL, plus SIN[K] → SIN and MAR[K] → MAR
Grid 2: [I]T IS → 'TIS and [I]RED → RED, plus BIT[E] → BIT and AID[E] → AID
Grid 3: [D]ICE → ICE and [D]OWN → OWN, plus CAP[E] → CAP and SIR[E] → SIR
Grid 4: [E]DEN → DEN and [E]SPY → SPY, plus EWE[S] → EWE and SON[S] → SON



The affected cells are highlighted in green above. Reading the top-leftmost cells from Grid 1 through 4, and the bottom-rightmost ones in reverse order gives the words 'HIDE' and 'SEEK'. Noting that one of the 'Down' clues for Grid 1 informs us we need to add an 'and' between these words, we end up with a final answer of 'HIDE AND SEEK' - very appropriate for the solving process required for a set of gridless crosswords!