bipolar junction current basic operation
Two hole current components:


Since B-E junction is forward biased, electrons move from emitter to base and holes move from base to emitter. (The majority carriers are injected to the other side). The current due to injection of holes is \$i_{B1}\$.
The electrons injected from emitter move to the collector region but a small recombination happens in the base while this travel. This base-recombination current is \$i_{B2}\$.


It is true that these excess holes will get recombined. But the holes in \$i_{B1}\$ recombines in emitter region where as the \$i_{B2}\$ holes recombination happens in the base. Hence they are shown as two different components of currents.