Yeah, I'd factor that into major limitations with the space based laser systems. Only think I can think of that could work around that is if one used an array of lasers that could constructively interfere during boost phase that could cause some kind of major turbulence at the point of intersection (maybe along the lines of the laser collisions here[0]:

"Fülöp and colleagues argue that the energy problem could be overcome by splitting the laser pulse into two equal-energy pulses, which then hit the target simultaneously at different, precisely calculated angles of incidence (see figure). Through simulations, the team showed that when the laser pulses collide, a standing wave forms inside the solid target that increases the peak electric field. With the same pulse intensity used in previous experiments, their calculations suggest that the technique can double the energy of the proton beam and produce five times as many protons — all with far more flexible control parameters than required before.").

[0] https://physicsworld.com/a/laser-collisions-could-boost-prot...