Is it a common practice nowadays for headhunters/recruiters in Malaysia and Singapore to reach out to candidates via Whatsapp instead of the professional channel e.g. Linkedin?

Because not everyone checks their LinkedIn account often. There are people who aren't active and didn't respond/ see the PM even after few days. Whatsapp is certainly faster for them to reach out to you.

If you're not comfortable with that, make sure to remove your contact information from the page/ uploaded resume.

Yes, if you are always suspicious, don't send documents to them via WhatsApp but rather ask for their company email to share it to them. Otherwise, give them a call and speak with them as well.

Good practise this is. ask for official email when dealing with Recruiters or even with any banking/insurance.

and they are mostly Indians

New norm