Multiple target detection relies on receiving enough photons back from each reflected target. For instance if the first (closest) target is large, then it is likely obstructing the further target(s) from reflecting enough photons back. I'd recommen...

You can find a working platform.c at https://github.com/lamik/VL53L0X_API_STM32_HAL/blob/master/Drivers/VL53L0X/platform/src/vl53l0x_platform.cI performed a Google search for STM32 VL53L0X GitHub where I found this example. Please give this a try.