When I planned a route EDMS - LIPB, I started with a direct line EDMS-LIPB and then inserted the waypoints by editing the magenta line on the map (finger drag and drop) and later corrected the levels in the virtual radar window also by finger drag and drop. All fine.

After letting SkyDemon create the briefing pack, I found crazy level values in the descent profile. The virtual radar remained correct.

It happens in iOS and in the windows-desktop version too.

What did I do wrong?

It isn't clear what the "crazy values" are that you're reporting, but when you plan a route by clicking consecutive waypoints on the map, SkyDemon automatically sets the level for the legs to a level that is above the MSA for that leg. If you're planning in mountainous terrain that would probably explain a level of 12600 feet. As always, you can set the level of individual legs by dragging them in virtual radar or going into the Leg Properties window; or set the level of the route as a whole from the Flight Details window.

Yes, sure, but why does it correctly use all the corrected levels from departure, climb and waypoint to waypoint en route, but from the top of descent onwards it jumps to that initially calculated max level all the way „down“ to the destination…?

I'm guessing you planned the flight originally by clicking on your takeoff airfield and then immediately on your landing airfield, so you would have had a one-leg flight with a planned level of 12600. Perhaps you then made divided your flight up into multiple legs and adjusted some of them but not all, whereas it might have been better to adjust the overall route level as one.

Yes, I planned the flight originally by clicking on my takeoff airfield and then immediately on my landing airfield. That is most easy and I think preferable way.

The other way creating a route by adding up waypoints one by one from origin to the destination is for many usability and planning aspects far from the optimum solution…

So I then inserted waypoints and adjusted leg-levels, but not for the descent as this is then generated automatically and no more adjustable in virtual radar window. Even if you move single descent legs in radar up or down, they jump back to a straight line. But that is acceptable - as long as the log/list values would follow.

What I do not understand: Radar window is somehow correct, but the list in the log is not. Why does SD not just take the (finger-edited) values as shown in radar window and feed the log/list with these values automatically?

Editing every leg one by one is a pain (especially with elaborated approach routes) and if you change the overall level of the whole flight to let‘s say 5000, then you have the wrong 5000 in all these legs which would also be wrong. And editing via leg properties menu would be even more painful.

By the way: editing descent profiles is anyway subject to possible future usability improvements as one can not (at least I did not find out, how) edit step-down vs continuous approaches, pattern altitudes etc.
Instead there is always a straight line down to field elevation. But that could be another topic…

Could you please contact customer support about this? I am not able to help on here and talking through it (plus sending your route) is more likely to get us to an answer.