Relax and Z key bug?

Hello there,

So I have this problem:

I used relax tool near the ear in the green part I drew, and then the some random vertices moved around on the head as you can see. This happened to me before but I just ignored it, but this time it got on my nerves. Is this normal? Should I report this as a bug?

Plus, a lot of times, I join 2 meshes, go into edit mode, start editing, and suddenly I want to undo something and bam, my Z key stops working in Blender, UNDO WORKS, if I search undo or undo history and press it with my mouse everything works fine, but the shortcut Ctrl+Z doesn’t or going into transparent mode, because the Z key is like turned off or something @_@

Has this ever happened to any of you? Did you report it? Should I report it? This Z key part has been getting more frequent and annoying, so I went to report it and then I read I should try it on a different computer so I wanted to do that and reinstall blender on this pc, before I reported anything. Then again, I don’t really use my other laptop this time of the year.