According to posts on BitcoinPool's own forum, it appears that the missing payments issue is indeed more widespread than just the one single instance noticed before.
The user audaibnjad has so far tracked 2 more blocks for which is hasn't been properly paid.
http://www.bitcoinpool.com/forum/viewtopic.php?f=1&t=26Edit:
Also, it looks like the user accounts are getting (successfully) brute forced or dictionary attacked and they haven't put in any lockout measures or other some such to prevent it.
So I'll say this again, login and check your wallet ID. Change your passwords, and make them secure. If you get compromised and haven't checked your wallet ID, don't say we didn't warn you.
Edit2:
Also, more concerns from users that are seeing the tell-tale signs that the pool is being attacked by implementations of the pool-hopping exploit.
Just wanted to know, are there any plans to reduce the ammount of cheaters (mainly pool hoppers)? it seems that this pool's speed takes a dump whenever it's half way through solving a block.