A double bottom pattern can fail, most often when price breaks below the second low instead of breaking above the neckline, signaling the downtrend is resuming. The classic failure occurs when the price drops below the level of the second bottom after forming the pattern, indicating that sellers regained control and the support level was not strong enough.
If the pattern forms in an extremely strong downtrend, the probability of failure increases since sellers may still dominate.
The pattern relies heavily on volume confirmation, and a breakout without strong volume can often fail.
Place stops below the second low and skip setups where the higher-timeframe trend is firmly bearish.