Unique Particle CSS Styles Modifed During Grav + Gantry Upgrade

[thekenshow]

Upgraded a Grav v1.6.16 + Gantry v5.4.31 to Grav v1.7.27.1 + Gantry v5.5.8 and found auto-generated particles style that had been altered.

Example 1

The --- that precedes particle becomes -__:

g-menu-item---particle-PkeJW

To:

g-menu-item-__particle-PkeJW

Example 2

The --- that precedes particle becomes /__:

g-menu-item-parts---particle-GH8Dy

To:

g-menu-item-parts/__particle-GH8Dy

This breaks the CSS written for these particles, of course - what's going on here?

Screenshots

[thekenshow]

Following up, an SCSS selector with a structure like .g-menu-item-parts/__particle-GH8Dy will not even compile in Gantry.

[mahagr]

Sounds like a bug.