Ceiling springs move the player 2px less than they're supposed to.

[whatsGravity]

Ceiling springs don't move the player to below the spring correctly, causing (for example) buffered dashes out of spring hits to rehit the spring.

FrostHelper/Code/FrostHelper/Entities/VanillaExtended/CustomSpring.cs

Line 283 in 55fad84

player.SuperBounce(Bottom + player.Height);

In this context, player.Height=9, as the current collider is checking for interaction with entities, so is the hurtbox. The fromY passed into SuperBounce is therefore Spring.Bottom+9.

The start of SuperBounce looks like:

public void SuperBounce(float fromY)
{
    ...
    Collider collider = base.Collider;
    base.Collider = normalHitbox;
    MoveV(fromY - base.Bottom);

Here, the collider is set to the normal hitbox, so player.Height = 11, meaning that base.Bottom is 2 pixels lower than expected, so fromY = Spring.Bottom-2. I.e, you get moved 2px fewer down than you should, putting you back into the spring.

The simplest fix is likely to just add 2 to fromY when hitting a ceiling spring. But, this might not account for hitting the spring with unusual hitboxes, so a more robust solution might be needed.
I would submit a PR myself but I'd guess the old spring behavior should be legacied for TAS's, and I'm not familiar with how to do that.