With Boolean criteria the wildcard just matches within the word, ie up to a word break character such as a space or punctuation.
Your example:
R6*212
matches any word with R6 followed by (at some point) 212, e.g.
R6P00212
If you want to find R6 near to 212 use the NEAR operator, e.g.
R6 NEAR 212
Or if you want to find 212 AFTER R6 use Multi-line regex, e.g.
R6.*212