Search recursively in all files with the name ending in ".log" located in any subdirectory of the root directory, for a pattern that matches two digits, followed by a hyphen, followed by three letters, followed by a hyphen, followed by four digits.
grep -r '\[0-9]\{2\}-[a-zA-Z]\{3\}-[0-9]\{4\}' $(find /* -mindepth 2 -maxdepth 4 -type f -name "*.log")