"To move the goalposts" means to change the rules or expectations of a situation or goal in an unfair or unfavorable manner, often when someone is close to achieving it. Full definition
«You can't keep moving the goalposts on hard - working people you need to get to work, who need answers, deserve deadlines that the MTA can actually accomplish,» said City Councilman Jimmy Van Bramer. (ny1.com)
And indeed it was a successful year — comprehensive income of $ 18.7 million puts us on solid ground in an environment where the regulators keep moving the goalposts on how they define solvency for insurance companies. (practicepro.ca)
Or has the bleeding edge of physics moved the goalposts again? (realclimate.org)