A consistency rule limits the share of your total profit that may come from any single day. If the rule caps one day at 15% of total profit, and your best day made $2,000 out of $10,000 total, that day is 20% of the total and the rule is broken, even though you hit the profit target.
Firms use this rule to check that a trader can make money steadily rather than in one spike. The cap varies: For Traders, for example, sets 15% on its Instant plans and 35% on Fast Pro, and some plans have no consistency rule at all. The rule may apply only during the challenge, only while funded, or in both stages, so the stage matters as much as the percentage.
This rule changes how you should trade near the end of a phase. A trader who hits the target with one very large winning day may still need more trading days to dilute that day's share of the total. Rushing to finish can fail the rule that patience would have passed.
The common trap is assuming the target is the only pass condition. Check the consistency cap on the rules page before you start, and track your best day as a share of total profit while you trade. Prop trading can cost you every fee you pay.