The voiced alveolo-palatal sibilant fricative /ʑ/ can be found in Wu words like: thank you. 谢谢 is said to be read:
I'm seeing many resources online claiming that the reading can just be:
谢谢! Yá yà! Thank you!
This gives me the feeling that the inital /ʑ/ might be somewhat stigmatized, perhaps out of convenience or for other reasons.