What do we call this? stop loss bug?

I am currently play demo. Platform mt4 in android phone.
Yesterday I made $78 from balance $1200 from more than 10 trades (not all profit surely).
Problem today in a trade, stop loss hit, I re check the chart n conclude price should never hit the S/L,
price vs S/L was more than 1.5 pips gap in that exact minute.

Question: is case like this usual to happen in demo or live account?

Almost always, when a question like yours comes up, the answer is this —

The trader who feels he was unfairly stopped out was in a SHORT position, and was watching his position on a BID chart. (The BID chart is the chart on which he sold SHORT, at exactly the price displayed on that chart.)

When price moved against his position, the ASK price hit his stop-loss, while the BID price (which he was watching) was still below his stop-loss by the amount of the spread.


Thanks for the answer, I got it . But…
One more question. So if spread is non fixed, it is possible that broker suddenly widen the spread? And alot traders suffer because S/L will be hit.?

in my view that is the case with market makers according to me who trades against their clients. a broker providing pure ECN spreads and is not a market maker would not do that if he is a pure ECN broker in reality.