I'm a fresh user who just discovered Linux Mint in late December 2018. I've had been trying out ubuntu (10:04 ?) a couple off years ago. Never liked the thingy to open up programs in (start meny in lack off a better word) Cinnamon was for me a completely new experience. I like it a lot!
My fiancé who does not understand technology can use the computer without any hassle 
(except sound grizzle while using YouTube). I could not update to 19.1 due to lost graphics but it worked when they added it to the regular updater 
So to topic..
While changing from traditional taskbar to modern and back from modern looks, i've notice that my theme got back to standard settings.Trying forth and back, i become quite good at change the theme
I don't think it is an error but it would be nice if it stayed as i've had set it up.
/proud newbie user