Hi Tooki,
Thanks for your fast reply.
Indeed, I already try cleaning it with a tissue and a bit of water and alcohol (Alcolhol 70 DEG).
I also try turn on/off power many times...
I also doubt this is firmware issue, because I still can touch to all that button, but just some seconds later, it often jump touch to "Cont" or "Diode" mode...
"Then make sure your meter's mains power is properly grounded. Use another meter to test continuity to ground. (The back panel of the meter should be grounded."
=> Unfortunately, in my Vietnam country, we don't have a ground system, it's not easy to make a ground for my home.
About EM noise => yes, I have a Rigol DS1054Z.
While try reproduce this issue, all other equipment is turn off. I don't see any strange EM noise.
"P.S. I would not use the word "automatic" (or the short form "auto") to describe unwanted behavior -- that word indicates something happening on purpose, which is the exact opposite of what you mean here."
=> Yes, I also think some word such as "random" - because it's not intended.
Thank you again.