From my personal evaluation of film lenses on digital ...
.... it seems to be a generational thing. Some particular coatings that
have a desired effect on film have a negative effect with digital.
My Pentax SMC 30/2.8 is outstanding for both film and digital, as are
the newer Pentax-F 50/1.7 and Pentax-FA 50/1.4. But the "A" series
lenses (Pentax-A 50/1.7, 35/2, and 100/2.8 [non-macro]) are only
average lenses. There's some color fringing toward the edges unless I
correct the white balance.
So the answer is yes and no. Some film lenses don't perform well with
digital. But some do. It's not necessarily because they were film
lenses. There is a correlation, but it is not a causal relationship.

Conversely, digital lenses should always perform well with film,
especially with traditional b&w with its single-layer emulsion. In the
Pentax world, the new Pentax-DA 40/2.8 is a tempting new offering,
well-suited for both fomats. (But I'm not quite ready to shell out
$399 for it.) Yes, it's another pancake. And a pretty one at that.

Collin
KC8TKA