Partial fills are common in limit orders. If the target price you have set has been reached but there is not enough liquidity to fill your limit order, it may sometimes receive a partial fill or no fill at all due to its price restriction.
For example, if you place a limit buy order to buy bitcoin at your desired market price but the available bitcoin up for sale that matches the price restrictions you have set only runs up to half of your trade order, it will only be partially filled by 50%.