On early LEAFs like yours with 2 water pumps, they operate in series. So there is some circulation even if one pump is failing and it would be hard to detect a symptom other than the self-diagnosis signal that the pump communicates to the VCM.
I'd suggest getting set up of LEAF Spy, so that you can view the error codes. For pump 2, these are P31EA, P31EB and P31ED, which are reporting percent-duty cycles that fall outside of normal operating ranges. No doubt one or more of these codes are what your tech noticed. You could try using LEAF Spy to reset the error codes and see if they come back.
For these codes the problem can be either a failing pump, electrical harness, or the VCM itself. The harness is a simple continuity check. Checking the VCM appears to require the dealer's CONSULT device. You could ask if they ruled out the harness/VCM. If so and the code returns after clearing, then pump replacement would seem warranted.
(Edit: re-reading your post you say you don't see DTCs. perhaps this means the dealer cleared them and they haven't returned. I'd re-check occasionally)