@Pablo I cannot reproduce this.
With App version 4.0.16, I do this:
- Add a Text message action.
- In the "Receivers" field, select a country code (e.g. Sverige +46).
- After +46, write the rest of the phone number, like 701234567. The whole field then contains the swedish flag, followed by +46701234567.
- Press the plus button at the rightmost edge of the field.
- The phone number will now be added below and the Receivers field will be cleared.
- Repeat step 2-5 how many times you wish, if you need multiple receivers.
- Enter something in the body.
- Press the floppy disk icon in the upper right corner to save.
If you can't make above work, please take a screenshot or video and post it so we can take a look at it.