It is not something browser-specific but XML-escaping. It is likely to have the same issue in all browsers.
Initially loading of presentation and updating the presentation when some event occurs are two different REST API calls, so it is possible one of them to work and the other to have this problem. Which versions of vSphere Web Client and vCO are you using? Also, could you check if you have the same issue with apostrophes in non-localized (English) workflows?
