problem with scaling using setScaleY

hi everybody, i’m having a problem with setScaleY.

for small values this works great like this:

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it’s ok, the calculation is ok too.
but for large values (over 30 scale factor) cocos2d-x is showing the sprite (texture) like this:

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I try doing the calculation manually (for assert the correct values) and cocos2d-x shows the same result.
as side note, the texture is not repeating over the scale.

I don’t know how workaround this problem because the calculation and scale factor are correct.

best regards