Was there a contractual signed binding contract friend A, which his employment role&responsibility to work in Subsidiary, which salary is paid by HQ?

If yes, then it is contractual binding that he didn’t perform, thus required to be under PIP.

Bro how to PIP friend A / TS ?
Takde contract to subsidiary A also.
U ingat labour or IR office Bodo ke.

If no official transfer cannot do anything la.
If they try PIP it's like clear message they want to end you
So, if it goes to court, sure fire company lose.

No contract.

Just a transfer form signed by both parties of HQ and subsidiary

The original contract with HQ, is there are clause or term that HQ can transfer the employee to branch or subsidiary at their discretion?

If the staffs under Friend A took an effort to report to HR, that means Friend A made a big mistake or being so incompetent in a new role. Typically staffs will just vent among themselves or just find a new job if they feel dissatisfied.

Friend A reminded me with my ex colleague. He used to be a manager for marketing dept. Then he requested to transfer department to become manager for Operation.

It's a different work scope and expectation of the new position are heavier than his previous role.

When he requested to transfer back to old dept, he got the old position back, but management already see him in a different point of view. See him as incompetent.

End up he resigned from his job. Same situation. Already worked with company for more than 5 years.

Sometimes it's better to stay in a position that you already expert rather than taking a risk in doing something new.

Unless you quit your job and join a new company.