I had a few rescues that were the same, tame in the beginnig and then suddenly shy and scary, I never found out why. But very often they changed into tame again after some time.

Maybe, but I can't even do that with Storm now. When Mikesch started to tame, Storm went backwards a little bit. I can't pick him up now for more that a few seconds before he starts breathing hard and then starts kicking and struggling, and I can't get him on the scale anymore.

Christmas next year you can lift Mikesch up and he will sit on your lap, I am sure :)

That is good, step by step and lots of patience, he will trust you more and more every day:)

When Mikesch is under the bed, he can be pet, and will return affection.