Sorry for my impatience, anyhow. There's a bug about the player in frog suit sliding down.
The reason for that is:
The player is in frog suit and is about to slide down a slope with the down key.
As the player in frog suit slides down, its speed is set to 0 if its speed reaches 2 and greater while its .stand is 1. (Similar to when the player in frog suit lands on the ground, its speed will become 0, and when sliding, it does the same, except when its jump is cancelled.)
- Spoiler
So yeah, that is the reason that bug occured. Hopefully it will be fixed as soon as possible.
Here's the level: