Frozen river biome creates sugar cane

What I expected to happen was: no sugar cane generated on frozen river borders and by ice-covered lakes.

What actually happened was: sugar cane generates by ice. As the result, it breaks and drops as resource.

How to reproduce: just find Ice Plains biome, and a river intersecting it. It should be Frozen River. For example, examine seed -435130594162764786 at coord. 2712,-3778 and river borders nearby.

Note: it does not harm in the game, but it looks really weird, like a bug of word generator.