Well I think I'll better tell you a story(What's happened) & and then I'll explain.
So, I want to catch some pokemons. I go to Safari zone (My favourite zone) and... Shiny pokemon! I choosed Master ball to catch him, but instead... I lose my Master ball & Shiny pokemon. But map doesn't said what I loose pokemon with my pokeball. I very sad about this, but it's also a bug. And I decided to tell about it.

thats quite weird.. i havent seen a master ball fail..

i dont know i think this could be a glitch because i dont think i have ever seen a masterball fail and if it did it should say so hopefully staff will check this out

Maybe your masterball glitch is possible. Did you have another screen on? I noticed that when I have multiple screens that the Pokemon I may be catching disappears when loading another screen.

I actually remember seeing this glitch a very long time ago. I remember that I was trying to use a masterball and the site lagged for about 3 seconds and the pokemon was never caught and I was minus one masterball.

Not always, but usually gets Masterball not catch. Sometimes this happens to me.

i have not experienced this glitch but if there is a glitch like this then Da Man please fix this :)
btw i think if anyone experiences this again, he/she better put up a S.S