[...]However, there have been cases where the frequency of job changes was excessive. Especially, when an applicant has a pattern of leaving a company within three months or less, it raises questions about potential underlying issues.[...]

As a UX Designer you are supposed to know the basics of cognitive psychology, at least for the fact that UX root is there.

Thus you should be able to control your own bias, and this is a galactic one.

Where are the proof of what you are saying? where are the data? where is the critical thinking? nowhere...

[...]The three-month mark is typically when the probation period ends, [...]

According to who? what company? what country? We are the end user of your article, and we are interacting with it, are you aware that your end user is spread around the world?

The probation period, which typically in the vast majority of the countries is dictated by the law, not by the company per se, it's a catch'em all approach, it does not distinguish between jobs, companies and task, this means that, BEING HUMAN CENTERED what someone get in 3 months, it's not necessary what someone else get.

For the records, there's a research online within HR, where the onboarding time has an average of 6 months, which is much more likely in tune with the many interactions a new employee face. For example, in Germany, vast majority of companies have a probation time of 6 months, which is beyond the law requirement but it greatly help both, employee and candidates to understand if is the right fit.

[...]and individuals are expected to develop a solid understanding of their roles and responsibilities.[...]

According to who? you are assuming 3 months = to this. And candidates thate are neurodivergent will align with the others? did you think if neurodivergens were among your resumes?

Jesus this is a Human Centered role born in the end of the 77s and from 2006 we have created a generation of crippled UXers

[...]If they are unable to endure that period and decide to resign or are laid off, it means we have to go through the process of hiring someone new, which requires a significant amount of time and effort.[...]

Bias, bias bias. Make a favor to your company, do not be involved in the hiring process.