Why do some browsers render this unicode character using the wrong font, apparently at random?

I am developing a website which requires use of the unicode symbol "S with caron" (0x161). The website uses the free Palanquin font, which does support this character - however, some machines incorrectly render this particular character in a different font. For example:

Note that in the incorrect example, the correct font is being used for other characters, even for those containing unusual diacritics. Crucially though, there is no obvious pattern about which machines are affected. Using browsershots.org, I have seen the issue occur on Chrome, Firefox, IE and Edge on both Windows and Linux - yet I have also seen the correct rendering on all of these browsers. I have also seen different outcomes on machines which are using the same version of the same browser.

I have tried pasting the character directly into the HTML as well as using the escape code š, both of which result in the same issue.

• Does anyone have any idea what could be causing the issue?
• Are there any suitable workarounds if it is not possible to rectify the issue?