Minecarts Lose Velocity When Approaching Slope

[Typhoon-365]

This bug is still present, I'm using CopperRails 1.0.5+mc1.21 on Fabric.

In the screenshot - minecart on the copper track (right) will only reach the redstone pillar while the minecart on the vanilla (left) powered track will reach the gold pillar.

Edit: this is with a player in the minecart.