[asherkin]

The root of your problem seems to be:

Constraints on character values Characters that are specified using octal or hexadecimal numbers are limited to certain values, as follows: 8-bit non-UTF mode less than 0x100 8-bit UTF-8 mode less than 0x10ffff and a valid codepoint 16-bit non-UTF mode less than 0x10000 16-bit UTF-16 mode less than 0x10ffff and a valid codepoint 32-bit non-UTF mode less than 0x100000000 32-bit UTF-32 mode less than 0x10ffff and a valid codepoint Invalid Unicode codepoints are the range 0xd800 to 0xdfff (the so-called "surrogate" codepoints), and 0xffef.

https://www.pcre.org/original/doc/html/pcrepattern.html