I just tried it with an older version of Icy: Icy 1.9.7.0

With this, I can open my files. Using Seperate Files it gives me the series selection window, allowing me to open all files in a group.
When using Group Files it gives me the tiled image again.

With this, I can atleast analyse my data now using an older version. But it would be nice if this was fixed soon.