Claiming that a potentially obvious invention was in fact surprising is not a basis for invalidating the subsequent patent or holding the filing to be fraudulent -- there is no indication that the use of the word caused the patent to be awarded. Subsequent attempt to enforce the patent rights therefore not a sham.
http://media.ca1.uscourts.gov/pdf.opinions/17-1714P-01A.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.