(This is not new in 5.09, it has been here earlier as well)
I discovered this bug using adsr, and later discovered that it's the
same with linseg, possibly also other line/exp generators.

The shortest segment possible with adsr is 1/kr, shorter segments will
not be generated.
The attached csd produces a correct amplitude envelope if ksmps = 100,
but no envelope is generated if ksmps = 200.
(The envelope will be a square window with amplitude = sustain level)

Oeyvind