Technically speaking you just placed a cake at yourself. Literally.

It couldn't detect a blank pixel to move into it, cuz it always failed by finding obscured pixels, cuz it's inside of your hedgehog.

And no, you are not the only one that this happened to.

If that happened and for the next update, The cake should be instantly exploded without manually pressed "fire" button, i mean the cake would be automanually have their position set for this.

I agree this looks like a bug. The video shown is over a minute long, but the cake should have exploded long before. It's obvious the cake was detonated manually at the end.

So at the very least, the bug is that the timer does not even start.

Cake doesn't have a timer, never had, it actually has fuel.
The more distance and curves it walks the nore it consumes.

If it gets stuck and runs in the spot without actually moving, it can take several ninutes for it to consume the fuel.

Not sure if we fixed that issue in dev already, I'll check that later.

Probably when walking downhill it should consume minimum, as a neutral gear in cars...

Ah, this explains it.

My idea to fix this issue is the following:

Make sure the cake always consumes a guaranteed minimum amount of fuel per time unit. This consumption must be less then it would take by, let's say walking on a perfectly flat surface.

This would guarantee that all cakes will explode in a reasonable amount of time even when they're stuck.
The downside might be that this could reduce the maximum walking distance a bit, so some playtesting should be done before fixing.

The idea is similar to the usage of the freezer: It still consumes fuel when you move it around.

EDIT: Okay, my idea is not new, haha.