Yeah, I think I had something like this once when developing too, I thought it froze, but after a minute or so it worked.
And for the issue with inside the platforms, I had initially the issue that was able to get stuck inside if you are in there, so I had to do it so that the collision activates when the player is out of the collision zone. I really wanted to make them activatable if inside, by making the mesh already visible, so that the player knows it is activated.
Otherwise not beeing able to activate if inside felt even more strange and unwanted for me, resulting in more trial and error.
It is more or less the downside, that it is sometimes hard to activate. What I usually do is doing small jumps, not too far away from the platform I am standing, landing back on the platform, until I see that the platform was revealed. Basically controlled jumps back and forth trying not to fall down. And then I can safely jump on.