Northdhoreshells is right. The glitch stopped suddenly. Hope it doesn't come back! Now I've another question... why does it become a different font and bigger size when i do cut and paste in the same note? this is also a recent problem.
I am having the same probem on my Note 5. When I typed numbers or alphabets, "$" or other symbols came up. However, there is no problem when I type on the same note on my PC platform. It's been like this for the past week. Hope Technical Support can do something about it soon. Thanks!