"losing its validity" is a correct and commonly used phrase in written English.
It is typically used to describe a situation where something is no longer considered true or valid. Example: As scientific research continues to advance, theories that were once widely accepted are now losing their validity.
Other large-scale processes may still allow long-range prediction, but the more detail one asks for in a forecast, the sooner will it lose its validity.
Sensitive data must be stored before a specific deadline, otherwise it will lose its validity.
The very structure of hierarchy of levels has lost its validity, even for those who believe in it as a model of autonomy of levels rather than as an image of fundamentalism.
It's an idea that worked in the 60's, but lost its validity beginning in the 70's when the car market became global".
Subsequent work has shown that the relationship loses its validity at higher pressures, but more complicated expressions that more accurately match experimental results can be derived.
It is shown under which conditions the widely used relation Rg2 = R2/6 loses its validity.
The tension between expediency and morality lost its validity in the sphere of politics.
The electrical model loses its validity when the resonators enter a nonlinear regime of motion, which is shown to occur either by mechanical stiffening or electrical softening.
Microelectromechanical systems (MEMS) occupy a special place in the hierarchy of physical models, namely in the region where continuum theory starts to lose its validity.
Those criteria allowing for the defence to gain the upper hand over the offence generally do not apply to revisionist states, as the rational logic established above loses its validity with regard to powers attempting to change the status quo.
