Do you want to request a feature or report a bug?

Bug?

What's the current behavior?

Date and time ranges use em dashes (—) between the start and end, except for week ranges that use hyphens (–).

What's the expected behavior?

The typographically correct dash to use is the en dash (–). This according to most style guides, such as the one from APA, American Psycological Association.

Using en dashes in ranges also increases the chance that screen readers reads the dash as "to" instead of skipping over it.