[BUG] RegEx fails to detect some Unicode char if prefixed by other characters

Is there an existing issue for this?

• I have searched the existing issues

Description of the Issue

RegEx fails to detect Unicode character (Ex: 𝘰) if prefixed by other characters (Ex: N)

Steps To Reproduce

1. Open Notepad++ and create new .txt file
2. Paste below lines in new text file

No
N𝘰
𝘰

3. Open find/replace dialogue box and find [NnƝ]+[Ooοᴑօ0𝘰]+
4. Then, find [Ooοᴑօ0𝘰]+

Current Behavior

Find [NnƝ]+[Ooοᴑօ0𝘰]+ detects characters only in the 1st line in N++ but detects characters in 1st and 2nd lines in regex101

Find [Ooοᴑօ0𝘰]+ detects characters in all three lines

Expected Behavior

Find [NnƝ]+[Ooοᴑօ0𝘰]+ should detect characters in 1st and 2nd lines

Debug Information

Notepad++ v8.7.9   (64-bit)
Build time : Mar 26 2025 - 03:20:28
Scintilla/Lexilla included : 5.5.5/5.4.3
Boost Regex included : 1_85
Path : D:\Data\usb x64\Notepad++\notepad++.exe
Command Line : "D:\Mobile\internal\Books\Longevity, starting from being - East Sea Fish Head.txt"
Admin mode : OFF
Local Conf mode : ON
Cloud Config : OFF
Periodic Backup : ON
Placeholders : OFF
Scintilla Rendering Mode : SC_TECHNOLOGY_DEFAULT (0)
Multi-instance Mode : monoInst
File Status Auto-Detection : cdEnabledNew (for current file/tab only)
Dark Mode : ON
OS Name : Windows 11 Home Single Language (64-bit)
OS Version : 24H2
OS Build : 26100.3476
Current ANSI codepage : 1252
Plugins : 
    AutoSave (2)
    BracketsCheck (1.2.2)
    ComparePlus (1.2)
    DSpellCheck (1.5)
    ExtSettings (1.3.1)
    FileFinder (0.3)
    Linefilter3 (1)
    MenuIcons (2.0.7)
    mimeTools (3.1)
    nppAutoDetectIndent (2.3)
    NppMenuSearch (0.9.6)
    NppTextFX (1.4.1)
    _CustomizeToolbar (5.3)

Anything else?

No response

Start by reproducing the pattern in the Find/Replace dialogue using the three lines and compare the two searches. Trace the Unicode matching behavior in the regex implementation identified by the Boost Regex version, then verify that [NnƝ]+[Ooοᴑօ0𝘰]+ matches the first and second lines without changing the existing single-class behavior.