Yes, the the Basic ESC R3 does send small amounts of reverse current/a back EMF voltage spike back to the supply when reversing rotation or stopping a motor/thruster. This active braking is baked into the BlHeli_S firmware the Basic ESC runs, but the spike is a very small amount of energy and should not affect anything unless it is particularly sensitive.
This is of no concern at all for a battery, and most power supplies have no issue as well. If running the thrusters in air this spike in somewhat greater, and some more sensitive power supply models can react to the short instantaneous reverse current by tripping their internal protection and temporarily shutting off. In general though, we have never seen this happen in actual use underwater, water does most of the braking.
Unfortunately there is no way to completely disable this without significantly modifying and recompiling the firmware, we have spoken to the BlHeli developer about this and it would take a lot of work to change the behavior without causing other issues.