A PIIA is a contract that an employee (usually an individual working in a research-oriented position) that indicates that any inventions that the employee creates during their term of employment belong to the employer. Some states offer restrictions on what can be included in the contract.
If you sign a contract there is potential that it is enforceable. In the US, much of that centers on whether or not the contract was written properly and includes all required information. Its validity is not based on whether or not you signed any other agreements.
Before signing a contract, you should consult an attorney. If you need some help,would be happy to put you in touch with a skilled contract attorney. Our rates are reasonable and we offer fast communication. Please reach out to us if we can be of assistance.