you could have some uuencoding issues based on different browser setups and javascript versions.
We do see this sometimes but it's very small numbers so for the most part we don't worry about it since whatever you are dynamically building you have stored in a previous variable.
however, you can always create a processing rule to try to see if any of those strings are there in the variable then just re-create it (or forget the dynamic variable and create it in a processing rule always)