Adobe Illustrator - Brush Size Changing

[Don29431766o1gt]

A pet peeve I've always have with Illustrator is that when I use its brushes to draw, every so often it would always go back to 1 pt size. I'm able to fix this by just doing a random stroke and then setting the size to what I want again, but I'm getting tired of doing that since it just wastes time. Is there a way to keep the brush size to what you want and not have the program switch to 1 pt randomly?

I appreciate any help!

[Monika Gause]

I suppose you have already turned off the "New art has basic appearance" setting?

Are you drawing with a Wacom or other tablet and you use the pressure to set the line weight? 

[Ares Hovhannesyan]

Which type of brush you are using? I can't reproduce your glitch?