If this perverse incentive were true, then you would expect the medical care costs to rapidly increase after the passage of ACA, but medical trend has actually slowed down since then[0] [1].
You can also look at the total dollar spend on hospital and medical expenses for the entire health insurance industry [2]. After the passage of ACA, there was a large increase in medical spend as more people obtained insurance coverage, but the increase in medical expenses year over year has settled back into the 5% range, which doesn't seem that perverse.
[0]https://www.statista.com/statistics/720767/medical-cost-tren...
[1]https://www.pwc.com/us/en/industries/health-industries/libra...
[2]https://content.naic.org/sites/default/files/2021-Annual-Hea...