ORA-36691: (NTEXTCNV02) Invalid escape sequence in argument to UNISTR function: [string].
Cause: The user called the UNISTR function on a string that had an invalid escape sequence. The only valid escape sequences in UNISTR are 1.) an escape-escape sequence, and 2.) an escape, followed by exactly four hexadecimal digits.
Action: Make sure that all escape sequences in UNISTR arguments are exactly four hexadecimal digits. To represent codepoints whose value is less than 0x1000, use preceding zeros. WRONG: 0x10; RIGHT: 0x0010.