Yep. Every transaction you make potentially leaks a little information about other transactions to/from your bitcoin wallet.
That's why I always say "bitcoin anonymity is complicated" and "bitcoin transactions are more private than credit card or bank transactions, but less private than cash transactions" or "staying completely anonymous while using bitcoins is hard."
And that's why you won't find (or, at least, shouldn't find) any claims that bitcoin is anonymous on the bitcoin.org home page or in the bitcoin source code.
What can you do? Use separate wallets. Make your donation address an instawallet or mybitcoin address that you don't use for anything else.
You must create a separate wallet for each of the donation options. Then the security will be much higher if you immediately post your main bitcoin wallet. Anonymity is still present, but it is not so anonymous that it would not track the conclusions and transfers of large amounts. Be careful with your transactions.