This is currently how Urshifu is displayed on Team Preview in S/V:
This is in fact the same sprite for both the Single-Strike and Rapid-Strike forms.
Up until generation 8, every pokemon that has multiple forms had one of two behaviours in team preview:
a) Has a unique minisprite for every form, such as the rotoms (which in turn, allows ps to demonstrate their battle sprite for team preview)
or
b) Defaults to their "base form", such cases include Arceus defaulting to normal form, silvally defaulting to normal form.
(This defaults to showing their normal type battle sprite)
Urshifu is an anomaly to how showdown currently displays their pokemon, because currently we simply display the battle animation that corresponds to the team preview sprite. However, Urshifu's base form for it's Team Preview sprite is neither it's Single-Strike, or Rapid-Strike form, but rather some "Urshifu-Neutral" form, which has no correlated battle animation.
To rectify this problem, Showdown simply decided to display it's Single-Strike form as it's "base" form, since it is considered the first of the two forms. While this is technically inaccurate, it's considered better than showing a blank battle animation at team preview, as well as avoiding the need to make custom cursor view descriptions of "This could either be Urshifu-S or Urshifu-R,".
The idea of making the second typing a question mark on cursor view is a good idea in my opinion, however it would be more suited for the Suggestions forum.