The phrase "flux adjustments" refers to making changes or corrections to a particular situation or system that is constantly changing or fluctuating. It involves making timely modifications to adapt and maintain balance or stability. Full definition
This also gives us more confidence in the results from the models still using flux adjustment. (ipcc.ch)
It does say that the results for about half of the models involved such flux adjustments. (sjsu.edu)
Actually the models do not do all that well even for zonal temperatures until exogenous fudge factors, called flux adjustments are included. (sjsu.edu)