Whatsapp Click-to-Chat "Couldn't open link" Error Chrome Android/iPhone

If you use https://api.whatsapp.com/send instead of https://wa.me/ you don't need to specify a phone number.

e.g

https://api.whatsapp.com/send?text=Your%20Custom%20Text

It seems that chrome does not accept click to chat without a number specified. Once there's a number in the URL it works just fine.
Unfortunately I did not find a hack to get around it. Neither of this worked:
https://wa.me//?text=Hello%20World
https://wa.me/0/?text=Hello%20World
only if a proper number is specified it will open WhatsApp, but has the recipient already pre selected (the number we provide).

I tested it for a client about 2 weeks ago, when it still worked. So the last update of Chrome (from Aug 26) seems to be the problem...