Some sequencer fustration and CD40xxB replacement question.

[Theo]

I had some problems with a new version of a 4017 based sequencer I did years
ago.
Problem is the clock pulse.
Turns out not all 4017 are created equal.
The CD4017B I used in the original has a smith trigger on the clock input
and allows for unlimited clock rise and fall times.
The CD4017BC I used in the new unit has no smith trigger and 5u sec max rise
and fall times. :((
Does anybody know a modern 40xx series that DOES do direct replacement for
CD40xxB?
Also, are this kind of hidden differences common between logic manufactures
?
It is the first time I encountered such a small but essential difference
among supposedly 'identical' ICs

Reg. Theo