Resolution: If standalone version of Hawk (5.1.0) is installed over an existing BE 5.1.2 setup, it will downgrade the existing AS version from 2.1.2.116 to 2.1.2.107 (as-logs shows 2.1.2.107).
Restoring only $AS_HOME/lib from another machine will help restore AS to version 2.1.2.116. The AS Version can be verified in as-log file.