I finished the complete collection on my iPhone over the past few months(2633 problems) and made a log of the problems that don't work. Basically, any problems with a letter mark "A/B" in them don't function, some problems will crash the app when you open them, and a few will say the correct solution is wrong when there is no other line possible. (I may post those later for verification by stronger players) The Android app on my friend's phone had the same issues, with an additional problem of crashing when scrolling through some sets. (It also lacks the Iphone app's search function, so you can't jump to a problem.)

Here's the list of non-working problems, by set. Regular font means letter mark, bolded problems are the ones that crash, underlined are the ones I think have no solution, italics have a letter mark but you can still "solve" them.

Beginner: No errors, although possibly some duplicate problems

Pre-inter(Easy): 10344, 10358, 10361, 10362

Pre-inter(Hard): 20120, 20125, 20315, 20463, 20545, 20550, 20773, 20802, 20809, 20816, 20818, 20821, 20833, 20852, 20885, 20889, 20893, 20898, 20901, 20907, 20909, 20911, 20921, 20936, 20944, 20945, 20958, 20959, 20960, 20962, 20969, 20971, 20986, 20990, 20991, 20996, 21016, 21019, 21031, 21083

Intermediate(Easy): 30038, 30039, 30122, 30354, 30378, 30380, 30386, 30390, 30397

Intermediate(Hard): 40223

Advanced(Easy): 50073, 50103, 50105, 50121

Advanced(Hard): 68029, 60084, 60100, 60107, 60110, 60113

EDIT: Found solutions to two of the problems.

Wow, this is a very good data. You should sent it to WBaduk or post it on their forum, maybe they could fix these app thanks to your feedback.

And a second Wow - for doing all these tsumego!

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Tsumego/Tesuji apps for iPad, iPhone & Android devices:http://www.lifein19x19.com/forum/viewtopic.php?f=18&t=7511

My friend discovered yet another glitch in his Android app; he can play a random move, then tap another part of the screen quickly and the solution line will start playing out. It doesn't seem to happen in the Iphone version or I would have been tempted to cheat a lot more in the advanced problem sets.

In the iphone app you can cheat after you have found the first correct move: After that move you can tip on your last played stone and the next move of the solution would turn up. Strangely, you have to tip that stone again to see the white response. There seem only very few updates to this app; however at least it is more usable for me than the windows wbaduk client.

Now that you mention it, most of my problem books seem to share this "bug": you can simply look up the answer! Imagine that..

I'm not sure if I can follow you. The problem with the wbaduk app is that I sometimes accidentially tip on the last stone instead of my intended move (the touch screen is not that big...) and then the app plays another move (the correct one) instead. So I get the correct variation even if I didn't wanted to look it up. I would call this unexpected behaviour - i. e. a bug. Fortunately, it seems that it does not happen on the first move.

If you just wanted to express that - since it's a free app - I have to live with it, I'm fine with that, too

So you think the author accidentally introduced this kind of behaviour, in contrast to intentionally providing it as an easy way for the users to check the solution? Hm.
I can't tell since I don't use any "apps", but it sounds like intended behaviour to me.
How would one normally go about checking the solution in that "app"?

Also, if this is continually a problem for you, I think you "click" too fast (instead of carefully reading out all variations beforehand).

I have a "problem" with problem #30307 on "intermediate easy" level.

The start position is

Click Here To Show Diagram Code

[go]$$B
$$.........|
$$.........|
$$......O..|
$$.....O...|
$$...XXXOO.|
$$..X.OOXO.|
$$.X....XO.|
$$.......O.|
$$.........|
$$----------[/go]

In the app, the following sequence is considered as "correct":


However there is a very simple alternative for white at first move, which seems to spoil the solution:



Did I overlook something essential?

I think you're correct, unfortunately. There's actually quite a few problems like this, I was going to do a follow-up post categorizing them separately, but my Iphone was stolen recently. I also haven't had any luck getting a hold of Wbaduk to see if they can update the app, maybe someone here who speaks Korean could try.