PCRE engine matches ä (ASCII char 228) to other diacritics

[marcrebel]

in the current () version a single ASCII character with a diacritic is matched by the PCRE engine to all other characters with diacritics as well.
The JavaScript engine matches as expected ( eg. "ä" only to "ä", not ê etc.).

Side note: on hover over the right sided match counter the black detail box reports "No match found in nn characters" despite the counter showing n > 0

(Info: https://regexr.com/45vjd)