Elytra equipped in the "Cape" Trinkets slot when using the Elytra Slot mod* don't show up in the armor bar when the "Item Type Bar" config option is enabled, as they do with Elytra equipped normally in the Chestplate slot.

Not really a bug or an incompatibility, but would be a cool support feature to be included.

*Elytra Slot by TheIllusiveC4, v6.3.0+1.20.1, dependent upon Trinkets by Emi, v3.7.2, in 1.20.1 on Fabric 0.15.6.