I have never seen that happen in PF2e printed adventures. A lot of the time they use monsters straight out of the Bestiary without modification, and when they don't they usually put the statblocks in the back of the AP so that they can all be referenced from wherever they need to be.

I just pulled down my copy of "The Enmity Cycle" (the closest Paizo adventure I have at hand). It's a level 4-6 adventure published in 2023. I haven't read it since shortly after I bought it, but the encounters go like this:

• The first encounter is with 4 bandits, and it references the Gamemastery Guide directly for their statblocks (though you can also get them on AoN). There is a note about a change to their favored terrain and what skill they roll for initiative (in PF2e, you can roll different stats for initiative depending on what you're doing; usually it's perception, but in this case, the bandits roll their stealth for initiative). It also notes their tactics (they try to threaten the party before attacking, and if you kill or capture two of them, the other two flee). This is standard for any encounter.

• The second encounter is with two sand wolves, the stat block for which is printed in the back of the module.

• The third encounter is with four gnoll hunters, taken straight from the Bestiary, page 178. If this were a more recent, post-OGL book, it would've referenced the Monster Core instead (page 208).

Then the party enters a temple (read: dungeon). Here the encounters are themed, but they don't pull any shenanigans like you mentioned. There are encounters...

• with two Scorching Sun Cultists (stat block inline with the adventure, mechanically and visually distinct from previous enemies) and a Filth Fire (Bestiary 2, page 110);

• with three cultists (this refers GMs back to the statblock printed above);

• with two cultists (again, reference back to the previous page) and a named priest of the cult (who is similar to the cultists, but also has some unique features befitting his position);

• with an atajma (an undead cleric monster who honestly looks super cool; reference to Book of the Dead p112, though I can't find it on AoN for some reason), and two more cultists;

• and an elite poltergeist (reference Bestiary, page 264). "Elite" is a template you can use to make a regular poltergeist more scary, so in fairness that is a way that they could do what you're saying, but they don't here.

That's the end of chapter one. Characters are supposed to level up around this time. In chapter 2, you fight:

• four elite nuglubs;
• a named jinkin boss;
• elite jinkin mooks;
• Usij cultists;
• sand wolves;
• several Scrapborn;
• two Scrapborn with the "weak" template;
• a named Ceustodaemon;
• a clockwork soldier;
• and a named gnoll priestess

...in various configurations, both before and in the dungeon. All of the enemies here refer to the same statblocks each time they appear, with the exception of the ones that have the "weak" template (which is like the "elite" template above, but in reverse). The sand wolves are the only repeated monster from chapter one, and they seem to be used as a power level indicator to show how much stronger you are, so they also appear with the same stats.

In chapter three there are more sand wolves and more cultists, some new creatures, some creatures that have been seen before, but none of them are reskinned soldiers dealing suspiciously different damage.

That was fun, incidentally. Makes me want to run this adventure I bought two years ago. Alas, the enemy of every campaign is the schedule.

Either you send mega-goblins, or you send MORE goblins.

A lower level party might fight 3 goblins fair and square, so 4 levels later they confront 6 goblins and 2 lieutenants.

The idea that the same enemy stays a challenge despite the level increase is actually what I despise in D&D. My character has grown in power, why is the rat from the beginning still able to down me?

And then you take the Test of the Starstone. As a joke, of course.