My browser / operating system: Windows NT 10.0, Opera 56.0.3051.52, Flash 31.0 (release 0)

1) for some reason, all effects work without stage 3d. not sure if this is a new update or my browser. (this isn't the actual problem, just a part of it.)
2) when i give a sprite the whirl effect, whenever i switch between stage3d and flash, the direction reverses.

make a sprite, give it the whirl effect, then press ctrl-m. it should switch direction, as though the value has switch from positive to negative or vice versa.
the whirl effect should go cw when positive, ccw when negative.

when I start as a clone
delete this clone

In the wiki they say this:
“If a project does contain graphic effects besides ghost and/or brightness, the project will automatically run in the Stage3D Player.”
Maybe it's the solution to resolve the glitches, i mean, when you use ctrl-m you switch back to the original player not to Stage3d.
Except that is reversed form mode to another i don't understand what's the problem, actually in a project you don't need to switch the mode? do yo?

you may not need to switch the direction, but i don't know if possibly one computer default to one state or another, and then it could definitely become a problem.
also, it defaults to stage 3d because flash didn't run those effects. now, i don't know if that's been changed, and if the whirl effect has been reversed on projects.

either way, it's still something that can definitely be fixed, and probably should be.

when I start as a clone
delete this clone

As i know, Stage3d is an API in flash player, means that it's not independent of the flash player, the graphic effects will run automatically for everyone using this API, and there will be no problem. Using this new API is a kind of fixation of the previous issues
Anyway, with the release of the scratch 3 all this problems related to flash player will disappear

it's not like this problem requires a rewrite, it's something that can just be quickly fixed.
also, whats the point of giving these excuses to just ignore the problem?

when I start as a clone
delete this clone

Men, i'm not a scratch developer to give excuses,
I'm just saying that it can be not a problem at all even if you see it like one