Yes, there is a problem with perspective property if it is a number and not a string. In 1.18.3 that property is applied, but if I set numeric value of 70, it will apply css value of 700px.
Also, what I'm trying to point to, there is a second problem, maybe connected to first one. If you look at my two previous examples, I have set perspective property as a string in both, and when I inspect code perspective have a value of 70px. So far soo good.
But in 1.18.3 rotated element have following property:
matrix3d(1.2, 0, 0, 0, 0, 0.848528, 0.848528, 0, 0, -0.707107, 0.707107, 0, -11.9098, 9.27076, 0, 1)
and in 1.18.2 (which is correct)
matrix3d(1.2, 0, 0, 0, 0, 0.848528, 0.848528, 0, 0, -0.707107, 0.707107, 0, 0, 0, 0, 1)
I hope that now is more clear. Also, sorry for my bad English