It absolutely is.

One of the largest downsides to an H-1B visa is that your immigration status is dependent on fulfilling the terms of your employment. If your employment ends for one reason or another, you will likely lose your lawful status. If you remain in the country without lawful status, you will start to build unlawful presence––too much unlawful presence will bar you from legally entering the U.S.

That happens if you get laid off or fired, and if you just up and quit because the conditions are too horrible:

Some of the most drastic consequences of losing your job may come if you are the person who terminates your employment. If you voluntarily quit your job, the employer will no longer be required to pay for the cost of your transportation back to your previous country of residence.

When you quit, your sponsored status will end immediately and you will begin accruing days of unlawful presence.

https://www.lawfirm1.com/non-immigrant-visas/h-1b-visas-employee-quits/

Is it that you didn't look this up yourself or did you think I wouldn't bring receipts?