Text disappers in 2D viewport

I just reopened a file I work on just an hour ago. And all the “T”, “y”,“c”,“M”, “F”,“R” are gone in top-viewport, but that appear again in front-viewport after 3D-rotating the text 90dg.

Fortunately they appear when I print.

Can you post post your model so we can duplicate this issue? Thanks.

Yes! Done! The issue fixed it self today, when I opened it today. It have happened before with other files but I can’t recall which files.