I own a Pixel 3. I have the APK client 1.0.48 installed on it because newer versions you can't get the messages back on your windows MPE program, I don't remember exactly the problem so I stayed with 1.0.48.
If something changed meanwhile with new APK client, let me know.
And I installed the latest 1.9.0 of course.
Exactly same behaviour as above, when I click on the clock, I start to write my message, the button "Send" becomes "Save". When I click this button, suddenly my screen smartphone is on. So I'm pretty sure MPE tries to save the sms on my smartphone.
But I suppose it depends on many android versions and also on what sms program you've got as default.
I use Next SMS on my android and I can program delayed sms on it. For those who are looking for a sms program who send delayed sms, try it, it works great.
I think this is an error to try to save the sms on the smartphone, the sms should be saved on windows and when the time is reached, MPE sends it as a regular sms as it does without the timing option.
Anyway thank you for this new version and this new option.
Cheers.