Quick answer: don't need to worry. You fund is perfectly safe
what's going on with blockchain? is the whole network effected by malleable attack?
Blockchain.info mistakenly thinks those transactions are double-spending but actually they are not. However, these are all cosmetic issue and no real harm could be done.
I have pm-ed piuk asking him to stop reporting double-spending on his service for now
everytime i send btc to my customer, i also send email notification of the txid. so now this practice should be avoided because huge chance that txid can be altered? and should we store the txid into our database? if not, how we determine each transaction from our end?
what should we do as merchant/developer to anticipate this malleability issue?