Text message thread disappears BUT ONLY IF IN DRAFT

any one else having this problem?

ENTIRE text message thread disappears but ONLY if i'm in the middle of drafting a reply and then leave the messaging application before sending the message.

Example:

I receive an SMS on an already long thread going back weeks. I then begin to compose a reply. Before i'm able to hit the send button, i get a notification from another app (e.g, Calendar reminder, or Whatsapp notification), and go to that other app. Doing so will immediately delete the ENTIRE text message thread, not only the draft.

I'm almost sure this is new behavior, as in the past, i'm 99% certain that i could leave the draft to do something else, and then come back to it later on.

Ideas, anyone?

I have over 11GB left on my device, and over 8GB left on my SD card. Am running 10.3.1.1779. A software update check says i'm running the latest software (i suppose for my carrier).

I leave text conversations in draft all the time and have never had them disappear. Very odd.

BlackBerryaholic by choice.