Quote:
$regsubex(é,/(.)/g,a) should be sending two bytes to pcre and since (*UTF8) is not used, two matches should happen and the output should be "aa". On the latest beta this is only "a"

Right, so basically there is no way to resolve this because scripters may have assumed that an accented e character will be seen as two characters in PCRE, ie. as UTF-8, instead of one character, athough I am not sure whether that is a reasonable assumption or how important it is. But for the sake of backwards compatibility I will be reversing this change in the next beta and noting the issue down in the code comments.